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Indian inventions & discoveries

This list of Indian inventions and discoveries details the inventions, scientific discoveries and contributions in India, including both the ancient and medieval nations in the subcontinent historically referred to as India and the modern Indian state. It draws from the whole cultural and technological history of India, during which architecture, astronomy, cartography, metallurgy, logic, mathematics, metrology and mineralogy were among the branches of study pursued by its scholars. During recent times science and technology in the Republic of India has also focused on automobile engineering, information technology, communications as well as space, polar, and nuclear sciences.

Inventions


  • Button, ornamental: Buttons—made from seashell—were used in the Indus Valley Civilization for ornamental purposes by 2000 BCE.[1] Some buttons were carved into geometric shapes and had holes pieced into them so that they could attached to clothing by using a thread.[1] Ian McNeil (1990) holds that: "The button, in fact, was originally used more as an ornament than as a fastening, the earliest known being found at Mohenjo-daro in the Indus Valley. It is made of a curved shell and about 5000 years old."[2]

  • Calico: Calico had originated in the subcontinent by the 11th century and found mention in Indian literature by the 12th when writer Hemacandra mentioned calico fabric prints done in a lotus design.[3] The Indian textile merchants traded in calico with the Africans by the 15th century and calico fabrics from Gujarat appeared in Egypt.[3] Trade with Europe followed from the 17th century onwards.[3] Within India, calico originated in Calicut.[3]

  • Carding, devices for: Historian of science Joseph Needham ascribes the invention of bow-instruments used in textile technology to India.[4] The earliest evidence for using bow-instruments for carding comes from India (2nd century CE).[4] These carding devices, called kaman and dhunakiwould loosen the texture of the fiber by the means of a vibrating string.[4]


Map showing origin and diffusion of chess from India to Asia, Africa, and Europe, and the changes in the native names of the game in corresponding places and time.
  • Chintz: The origin of Chintz is from the printed all cotton fabric of calico in India.[17] The origin of the word chintz itself is from the Hindi language word चित्र् (chitr) , which means a spot.[17][18]
  • Cotton gin, single-roller: The Ajanta caves of India yield evidence of a single roller cotton gin in use by the 5th century.[20] This cotton gin was used in India until innovations were made in form of foot powered gins.[21] The cotton gin was invented in India as a mechanical device known ascharkhi, more technically the "wooden-worm-worked roller". This mechanical device was, in some parts of India, driven by water power.[4]
  • Crescograph: The crescograph, a device for measuring growth in plants, was invented in the early 20th century by the Bengali scientist Jagdish Chandra Bose.[22][23]
  • Crucible steel: Perhaps as early as 300 BCE—although certainly by 200 CE—high quality steel was being produced in southern India also by what Europeans would later call the crucible technique.[24] In this system, high-purity wrought iron, charcoal, and glass were mixed in a crucible and heated until the iron melted and absorbed the carbon.[24] The first crucible steel was the wootz steel that originated in India before the beginning of the common era.[25] Archaeological evidence suggests that this manufacturing process was already in existence in South India well before the Christian era.[26][27][dubious – discuss]
  • Dock (maritime): The world's first dock at Lothal (2400 BCE) was located away from the main current to avoid deposition of silt.[28] Modern oceanographers have observed that the Harappans must have possessed great knowledge relating to tides in order to build such a dock on the ever-shifting course of the Sabarmati, as well as exemplary hydrography and maritime engineering.[28] This was the earliest known dock found in the world, equipped to berth and service ships.[28] It is speculated that Lothal engineers studied tidal movements, and their effects on brick-built structures, since the walls are of kiln-burnt bricks.[29] This knowledge also enabled them to select Lothal's location in the first place, as the Gulf of Khambhat has the highest tidal amplitude and ships can be sluiced through flow tides in the river estuary.[29] The engineers built a trapezoidal structure, with north-south arms of average 21.8 metres (71.5 ft), and east-west arms of 37 metres (121 ft).[29][dubious – discuss]

Cotton being dyed manually in contemporary India.
  • Incense clock: Although popularly associated with China the incense clock is believed to have originated in India, at least in its fundamental form if not function.[30][31] Early incense clocks found in China between the 6th and 8th century CE—the period it appeared in China all seem to have Devanāgarī carvings on them instead of Chinese seal characters.[30][31] Incense itself was introduced to China from India in the early centuries CE, along with the spread of Buddhism by travelling monks.[32][33][34] Edward Schafer asserts that incense clocks were probably an Indian invention, transmitted to China, which explains the Devanāgarī inscriptions on early incense clocks found in China.[30] Silvio Bedini on the other hand asserts that incense clocks were derived in part from incense seals mentioned in Tantric Buddhist scriptures, which first came to light in China after those scriptures from India were translated into Chinese, but holds that the time-telling function of the seal was incorporated by the Chinese.[31]
  • India ink, carbonaceous pigment for: The source of the carbon pigment used in India ink was India.[35][36] In India, the carbon black from which India ink is produced is obtained by burning bones, tar, pitch, and other substances.[36][37] Ink itself has been used in India since at least the 4th century BCE.[38] Masi, an early ink in India was an admixture of several chemical components.[38] Indian documents written in Kharosthi with ink have been unearthed in Xinjiang.[39] The practice of writing with ink and a sharp pointed needle was common in ancient South India.[40] Several Jain sutras in India were compiled in ink.[41]
  • Indian clubs: The Indian club—which appeared in Europe during the 18th century—was used long by India's native soldiery before its introduction to Europe.[42] During the British Raj the British officers in India performed calisthenic exercises with clubs to keep in for physical conditioning.[42]From Britain the use of club swinging spread to the rest of the world.[42]
  • Kabaddi: The game of kabaddi originated in India during prehistory.[43] Suggestions on how it evolved into the modern form range from wrestling exercises, military drills, and collective self defense but most authorities agree that the game existed in some form or the other in India during the period between 1500-400 BCE.[43]
  • Ludo: Pachisi originated in India by the 6th century.[44] The earliest evidence of this game in India is the depiction of boards on the caves of Ajanta.[44] This game was played by the Mughal emperors of India; a notable example being that of Akbar, who played living Pachisi using girls from his harem.[44][45] A variant of this game, called Ludo, made its way to England during the British Raj.[44]

The Great Stupa at Sanchi (4th-1st century BCE). The dome shaped stupa was used in India as a commemorative monument associated with storing sacred relics.
  • Palampore: पालमपुर् (Hindi language) of Indian origin[48] was imported to the western world—notable England and Colonial america—from India.[49][50] In 17th century England these hand painted cotton fabrics influenced native crewel work design.[49] Shipping vessels from India also took palampore to colonial America, where it was used inquilting.[50]
  • Prayer flags: The Buddhist sūtras, written on cloth in India, were transmitted to other regions of the world.[55] These sutras, written on banners, were the origin of prayer flags.[55] Legend ascribes the origin of the prayer flag to the Shakyamuni Buddha, whose prayers were written on battle flags used by the devas against their adversaries, theasuras.[56] The legend may have given the Indian bhikku a reason for carrying the 'heavenly' banner as a way of signyfying his commitment to ahimsa.[57] This knowledge was carried into Tibet by 800 CE, and the actual flags were introduced no later than 1040 CE, where they were further modified.[57] The Indian monk Atisha (980-1054 CE) introduced the Indian practice of printing on cloth prayer flags to Tibet.[56]

Wayang Kulit (shadow puppet) in Wayang Purwa type, depicting five Pandava, from left to right: Bhima,Arjuna, Yudhishtira, Nakula, and Sahadeva (Museum Indonesia, Jakarta). Ghosh, Massey, and Banerjee (2006) trace the origins of puppetry in India to the Indus Civilization.
  • Ruler: Rulers made from Ivory were in use by the Indus Valley Civilization in what today is Pakistan and some parts of Western India prior to 1500 BCE.[61] Excavations at Lothal (2400 BCE) have yielded one such ruler calibrated to about 1/16 of an inch—less than 2millimeters.[61] Ian Whitelaw (2007) holds that 'The Mohenjo-Daro ruler is divided into units corresponding to 1.32 inches (33.5 mm) and these are marked out in decimal subdivisions with amazing accuracy—to within 0.005 of an inch. Ancient bricks found throughout the region have dimensions that correspond to these units.'[62] Shigeo Iwata (2008) further writes 'The minimum division of graduation found in the segment of an ivory-made linear measure excavated in Lothal was 1.79 mm (that corresponds to 1/940 of a fathom), while that of the fragment of a shell-made one from Mohenjo-daro was 6.72 mm (1/250 of a fathom), and that of bronze-made one from Harapa was 9.33 mm (1/180 of a fathom).'[63] The weights and measures of the Indus civilization also reached Persia and Central Asia, where they were further modified.[63]
  • Seamless celestial globe: Considered one of the most remarkable feats in metallurgy, it was invented in Kashmir by Ali Kashmiri ibn Luqman in between 1589 and 1590 CE, and twenty other such globes were later produced in Lahore and Kashmir during the Mughal Empire.[64][65] Before they were rediscovered in the 1980s, it was believed by modern metallurgists to be technically impossible to produce metal globes without anyseams, even with modern technology.[65] These Mughal metallurgists pioneered the method of lost-wax casting in order to produce these globes.[65]
  • Simputer: The Simputer (acronym for "simple, inexpensive and multilingual people's computer") is a self-contained, open hardware handheld computer, designed for use in environments where computing devices such as personal computers are deemed inappropriate. It was developed in 1999 by 7 scientists of the Indian Institute of Science, Bangalore, led by Dr. Swami Manohar in collaboration with Encore India, a company based in Bangalore.[66][67] Originally envisaged to bring internet to the masses of India, the Simputer and its derivatives are today widely utilized by governments of several Indian states as part of their e-governance drive, the Indian Army, as well as by other public and private organizations.[68][69]
  • Snakes and ladders: Snakes and ladders originated in India as a game based on morality.[70] During British rule of India, this game made its way to England, and was eventually introduced in the United States of America by game-pioneer Milton Bradley in 1943.[70]
  • Stepwell: Earliest clear evidence of the origins of the stepwell is found in the Indus Valley Civilization's archaeological site at Mohenjodaro in Pakistan.[71] The three features of stepwells in the subcontinent are evident from one particular site, abandoned by 2500 BCE, which combines a bathing pool, steps leading down to water, and figures of some religious importance into one structure.[71] The early centuries immediately before the common era saw the Buddhists and the Jains of India adapt the stepwells into their architecture.[71] Both the wells and the form of ritual bathing reached other parts of the world with Buddhism.[71] Rock-cut step wells in the subcontinent date from 200-400 CE.[72] Subsequently the wells at Dhank (550-625 CE) and stepped ponds at Bhinmal (850-950 CE) were constructed.[72]
  • Stupa: The origin of the stupa can be traced to 3rd century BCE India.[73] It was used as a commemorative monument associated with storing sacred relics.[73] The stupa architecture was adopted in Southeast and East Asia, where it evolved into the pagoda, a Buddhist monument used for enshrining sacred relics.[73]
  • Toe stirrup: The earliest known manifestation of the stirrup, which was a toe loop that held the big toe was used in India in as early as 500 BCE[74]or perhaps by 200 BCE according to other sources.[75][76] This ancient stirrup consisted of a looped rope for the big toe which was at the bottom of a saddle made of fibre or leather.[76] Such a configuration made it suitable for the warm climate of most of India where people used to ride horses barefoot.[76] A pair of megalithic double bent iron bars with curvature at each end, excavated in Junapani in the central Indian state of Madhya Pradesh have been regarded as stirrups although they could as well be something else.[77] Buddhist carvings in the temples of Sanchi, Mathura and the Bhaja caves dating back between the 1st and 2nd century BCE figure horsemen riding with elaborate saddles with feet slipped under girths.[78][79][80] Sir John Marshall described the Sanchi relief as "the earliest example by some five centuries of the use of stirrups in any part of the world".[80] In the 1st century CE horse riders in northern India, where winters are sometimes long and cold, were recorded to have their booted feet attached to hooked stirrups.[75] However the form, the conception of the primitive Indian stirrup spread west and east, gradually evolving into the stirrup of today.[76][79]
  • Wootz steel: Wootz originated in India before the beginning of the common era.[25] Wootz steel was widely exported and traded throughout ancient Europe, China, the Arab world, and became particularly famous in the Middle East, where it became known as Damascus steel. Archaeological evidence suggests that this manufacturing process was already in existence in South India well before the Christian era.[26][27] 

  • Discoveries

    Agriculture


    Jute plants Corchorus olitorius and Corchorus capsularis cultivated first in India.
    • Cashmere wool: The fiber is also known as pashm or pashmina for its use in the handmade shawls of Kashmir, India.[81] The woolen shawls made from wool in Kashmir region of India find written mention between 3rd century BCE and the 11th century CE.[82] However, the founder of the cashmere wool industry is traditionally held to be the 15th century ruler of Kashmir, Zayn-ul-Abidin, who employed weavers from Central Asia.[82]
    • Indigo dye: Indigo, a blue pigment and a dye, was used in India, which was also the earliest major center for its production and processing.[86] The Indigofera tinctoria variety of Indigo was domesticated in India.[86] Indigo, used as a dye, made its way to the Greeks and theRomans via various trade routes, and was valued as a luxury product.[86]
    • Jute, cultivation of: Jute has been cultivated in India since ancient times.[87] Raw jute was exported to the western world, where it was used to make ropes and cordage.[87] The Indian jute industry, in turn, was modernized during the British Raj in India.[87] The region of Bengalwas the major center for Jute cultivation, and remained so before the modernization of India's jute industry in 1855, when Kolkata became a center for jute processing in India.[87]
    • Sugar refinement: Sugarcane was originally from tropical South Asia and Southeast Asia.[88]Different species likely originated in different locations with S. barberi originating in India andS. edule and S. officinarum coming from New Guinea.[88] The proccess of producing crystallized sugar from sugarcane was discovered by the time of the Imperial Guptas,[89] and the earliest reference of candied sugar comes from India.[90] The process was soon transmitted to China with traveling Buddhist monks.[90] Chinese documents confirm at least two missions to India, initiated in 647 CE, for obtaining technology for sugar-refining.[91] Each mission returned with results on refining sugar.[91]

    Mathematics


    The Hindu-Arabic numeral system. The inscriptions on the edicts of Ashoka (3rd century BCE) display this number system being used by the Imperial Mauryas.[dubious – discuss]

    The half-chord version of the sine function was developed by the Indian mathematician Aryabhatta.

    Brahmagupta's theorem (598–668) states that AF =FD.
    • Chakravala method: The Chakravala method, a cyclic algorithm to solve indeterminatequadratic equations is commonly attributed to Bhāskara II, (c. 1114–1185 CE)[100][101][102] although some attribute it to Jayadeva (c. 950 ~ 1000 CE).[103]Jayadeva pointed out that Brahmagupta’s approach to solving equations of this type would yield infinitely large number of solutions, to which he then described a general method of solving such equations.[104] Jayadeva's method was later refined by Bhāskara II in hisBijaganita treatise to be known as the Chakravala method, chakra (derived from cakraṃचक्रं) meaning 'wheel' in Sanskrit, relevant to the cyclic nature of the algorithm.[104][105]With reference to the Chakravala method, E. O. Selenuis held that no European performances at the time of Bhāskara, nor much later, came up to its marvellous height of mathematical complexity.[100][104][106]
    • Infinite series for Sine, Cosine, and arctangent: Madhava of Sangamagrama and his successors at the Kerala school of astronomy and mathematics used geometric methods to derive large sum approximations for sine, cosin, and arttangent. They found a number of special cases of series later derived by Brook Taylor series. They also found the second-order Taylor approximations for these functions, and the third-order Taylor approximation for sine.[107][108][109]
    • Law of signs in multiplication: The earliest use of notation for negative numbers, assubtrahend, is credited by scholars to the Chinese, dating back to the 2nd century BC.[110] Like the Chinese, the Indians used negative numbers as subtrahend, but were the first to establish the "law of signs" with regards to the multiplication of positive and negative numbers, which did not appear in Chinese texts until 1299.[110] Indian mathematicians were aware of negative numbers by the 7th century[110], and their role in mathematical problems of debt was understood.[111] Mostly consistent and correct rules for working with negative numbers were formulated,[112] and the diffusion of these rules led the Arab intermediaries to pass it on to Europe.[111]
    • Numerical zero: The concept of zero as a number, and not merely a symbol for separation is attributed to India.[113] In India, practical calculations were carried out using zero, which was treated like any other number by the 9th century CE, even in case of division.[113][112]
    • Pi, infinite series: The infinite series for π is now attributed to Madhava of Sangamagrama (c. 1340-1425) and his Kerala school of astronomy and mathematics.[116][117] He made use of the series expansion of arctanx to obtain an infinite series expression for π.[116] Their rational approximation of the error for the finite sum of their series are of particular interest. They manipulated the error term to derive a faster converging series for π.[118]They used the improved series to derive a rational expression,[118]104348 / 33215 for π correct up to eleven decimal places, i.e.3.14159265359.[119][120]
    • Sign convention: Symbols, signs and mathematical notation were employed in an early form in India by the 6th century when the mathematician-astronomer Aryabhata recommended the use of letters to represent unknown quantities.[95] By the 7th century Brahmagupta had already begun using abbreviations for unknowns, even for multiple unknowns occurring in one complex problem.[95] Brahmagupta also managed to use abbreviations for square roots and cube roots.[95] By the 7th century fractions were written in a manner similar to the modern times, except for the bar separating the numerator and the denominator.[95] A dot symbol for negative numbers was also employed.[95] The Bakhshali Manuscript displays a cross, much like the modern '+' sign, except that it symbolized subtraction when written just after the number affected.[95] The '=' sign for equality did not exist.[95] Indian mathematics was transmitted to the Islamic world where this notation was seldom accepted initially and the scribes continued to write mathematics in full and without symbols.[122]
    • Trigonometric functions, adapted from Greek: The trigonometric functions sine and versine were adapted from the full-chord Greek version (to the modern half-chord versions) by the Indian mathematician, Aryabhata, in the late 5th century.[123][124]

    Medicine


    Cataract in the Human Eye—magnified view seen on examination with a slit lamp. Indian surgeon Susrutaperformed cataract surgery by the 6th century BCE.

    Amastigotes in a chorionic villus. Upendranath Brahmachari (December 19, 1873 - February 6, 1946) discovered Urea Stibamine, a treatment which helped nearly eradicate Visceral leishmaniasis.
    • Cataract surgery: Cataract surgery was known to the Indian physician Sushruta (6th century BCE).[126] In India, cataract surgery was performed with a special tool called theJabamukhi Salaka, a curved needle used to loosen the lens and push the cataract out of the field of vision.[126] The eye would later be soaked with warm butter and then bandaged.[126] Though this method was successful, Susruta cautioned that cataract surgery should only be performed when absolutely necessary.[126] Greek philosophers and scientists traveled to India where these surgeries were performed by physicians.[126]The removal of cataract by surgery was also introduced into China from India.[127]
    • Inoculation and Variolation: The earliest record of inoculation and variolation for smallpoxis found in 8th century India, when Madhav wrote the Nidāna, a 79-chapter book which lists diseases along with their causes, symptoms, and complications.[128] He included a special chapter on smallpox (masūrikā) and described the method of inoculation to protect against smallpox.[128]
    • Leprosy: Kearns & Nash (2008) state that the first mention of leprosy is described in the Indian medical treatise Sushruta Samhita (6th century BCE).[129] However, The Oxford Illustrated Companion to Medicine holds that the mention of leprosy, as well as ritualistic cures for it, were described in the Atharva-veda (1500–1200 BCE), written before theSushruta Samhita.[130]
    • Plastic surgery: Plastic surgery was being carried out in India by 2000 BCE.[131] The system of punishment by deforming a miscreant's body may have led to an increase in demand for this practice.[131] The surgeon Sushruta contributed mainly to the field of Plastic and Cataract surgery.[132] The medical works of both Sushruta and Charak were translated into Arabic language during the Abbasid Caliphate (750 CE).[133] These translated Arabic works made their way into Europe via intermidiateries.[133] In Italy the Branca family of Sicily and Gaspare Tagliacozzi of Bologna became familiar with the techniques of Sushruta.[133]
    • Lithiasis treatment: The earliest operation for treating lithiasis, or the formations of stones in the body, is also given in the Sushruta Samhita (6th century BCE).[134] The operation involved exposure and going up through the floor of the bladder.[134]
    • Visceral leishmaniasis, treatment of: The Indian (Bengali) medical practitioner Upendra Nath Brahmachari (December 19, 1873 - February 6, 1946) was nominated for the Nobel Prize in Physiology or Medicine in 1929 for his discovery of 'ureastibamine (antimonial compound for treatment of kala azar) and a new disease, post-kalaazar dermal leishmanoid.'[135] Brahmachari's cure for Visceral leishmaniasis was the urea salt of para-amino-phenyl stibnic acid which he called Urea Stibamine.[136] Following the discovery of Urea Stibamine, Visceral leishmaniasis was largely eradicated from the world, except for some underdeveloped regions.[136]

    Mining

    • Diamond, mining, engraving, and use as tool: Diamonds were first recognized and mined in central India,[137][138][139] where significant alluvial deposits of the stone could then be found along the rivers Penner, Krishna and Godavari. It is unclear when diamonds were first mined in India, although estimated to be at least 5,000 years ago.[140] India remained the world's only source of diamonds until the discovery of diamonds in Brazil in 18th century.[141][142][143] Golconda served as an important center for diamonds in central India.[144] Diamonds then were exported to other parts of the world, including Europe.[144] Early references to diamonds in India come from Sanskrit texts.[145] The Arthashastra of Kautilya mentions diamond trade in India.[143] Buddhist works dating from the 4th century BCE mention it as a well-known and precious stone but don't mention the details of diamond cutting.[137] Another Indian description written at the beginning of the 3rd century describes strength, regularity, brilliance, ability to scratch metals, and good refractive properties as the desirable qualities of a diamond.[137] A Chinese work from the 3rd century BCE mentions: "Foreigners wear it [diamond] in the belief that it can ward off evil influences".[137] The Chinese, who did not find diamonds in their country, initially did not use diamond as a jewel but used as a "jade cutting knife".[137]
    • Zinc, mining and medicinal use: Zinc was first recognised as a metal in India. Zinc mines of Zawar, near Udaipur, Rajasthan, were active during 400 BCE.[146] There are references of medicinal uses of zinc in the Charaka Samhita (300 BCE).[146] The Rasaratna Samuccaya which dates back to the Tantric period (c. 5th - 13th century CE) explains the existence of two types of ores for zinc metal, one of which is ideal for metal extraction while the other is used for medicinal purpose.[146][147]

    Science


    Bengali Chemist Prafulla Chandra Roy synthesized NH4NO2 in its pure form.

    A Ramachandran plot generated from the proteinPCNA, a human DNA clamp protein that is composed of both beta sheets and alpha helices (PDB ID 1AXC). Points that lie on the axes indicate N- and C-terminalresidues for each subunit. The green regions show possible angle formations that include Glycine, while the blue areas are for formations that don't include Glycine.
    • Ammonium nitrite, synthesis in pure form: Prafulla Chandra Roy managed to synthesize NH4NO2 in its pure form, and became the first scientist to have done so.[148]Prior to Ray’s synthesis of Ammonium nitrite it was thought that the compound undergoes rapid thermal decomposition releasing nitrogen and water in the process.[148]
    • Bhatnagar-Mathur Magnetic Interference Balance: Invented jointly by Shanti Swarup Bhatnagar and K.N. Mathur in 1928, the so-called 'Bhatnagar-Mathur Magnetic Interference Balance' was a modern instrument used for measuring various magnetic properties.[149] The first appearance of this instrument in Europe was at a Royal Societyexhibition in London, where it was later marketed by British firm Messers Adam Hilger and Co, London.[149]
    • Mahalanobis distance: Introduced in 1936 by the Indian (Bengali) statistician Prasanta Chandra Mahalanobis (June 29, 1893–June 28, 1972), this distance measure, based upon the correlation between variables, is used to identify and analyze differing pattern with respect to one base.[157]
    • Raman effect: The Encyclopædia Britannica (2008) reports: "change in the wavelength of light that occurs when a light beam is deflected by molecules. The phenomenon is named for Sir Chandrasekhara Venkata Raman, who discovered it in 1928. When a beam of light traverses a dust-free, transparent sample of a chemical compound, a small fraction of the light emerges in directions other than that of the incident (incoming) beam. Most of this scattered light is of unchanged wavelength. A small part, however, has wavelengths different from that of the incident light; its presence is a result of the Raman effect."[159]

    Innovations

    • Public bathing: According to John Keay the Great Bath of Mohenjo Daro was the size of 'a modest municipal swimming pool', complete with stairs leading down to the water at each one of its ends.[166] The bath is housed inside a larger—more elaborate—building and was used for public bathing.[166][dubious – discuss]
    • Urban planning: Remains of major Indus cities (mature period c. 2600–1900 BCE) in what today is Pakistan and Western India, display distinct characteristics of urban planning such as streets crossing each other at right angles, well arranged rows of structures as well as neatly built, covered drainage and sewage lines, complete with maintenance sumps, running along backlanes.[167][168] Drains in the ancient maritime city of Lothal for example, designed to be able to take out the city’s entire domestic sewage and storm-water were mostly underground, and built to high levels of uniformity, whereby the slopes never exceed 1 in 10,000.[168][169] In terms of segregation, Lothal was divided into three districts: the citadel, the lower town and the dockyard, which were further divided into smaller administration centres, all having well planned infrastructure such as wide, straight roads along neatly arranged buildings to suit their purpose.[168][170] Such planning is also evident from remains of Mohenjo-Daro, a city to the north-west of Lothal, which appears to have been built adhering to a complex level of city grid planning.[167][171] This leads archaeologists to the conclusion that these cities were conceived entirely if not to a large extent before they were built—the earliest known manifestation of urban planning.[167][172][173][dubious – discuss]
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