The prime meridian is the imaginary 0-degree longitude line passing through Greenwich, London. Established in 1884 at the International Meridian Conference in Washington DC, it serves as the global reference for measuring east-west distance, defining time zones, and dividing the earth into Eastern and Western hemispheres. It aids international navigation and sets Coordinated Universal Time (UTC). Synonyms include the Greenwich Meridian or Geographic Longitude. Union education minister Dharmendra Pradhan declared on April 6 that it is time to establish “Mahakal Standard Time” (MST) in place of Greenwich Mean Time (GMT), claiming that Ujjain is “the original centre of time calculation.” Inaugurating the three-day ‘Mahakal the Master of Time International Conference,’ he stated that Ujjain, Kashi, Kanchi, and Puri Dham are “living laboratories” where science, art, culture, literature, and spirituality converge.The minister asserted, “Ujjain is the place where the Equator and the Tropic of Cancer meet, and ancient world time calculations were made. Therefore, the time has come to logically establish ‘Mahakal Standard Time’ (MST) in place of ‘Greenwich Mean Time’ (GMT). Even modern AI tools recognise that the original centre of time calculation is the area around Ujjain.” Therefore, the need is to re-establish the country’s scientific pride globally, he said. The scientific correctionHis specific geographical claim: “Ujjain is where the Equator and the Tropic of Cancer meet,” is scientifically untenable. The Equator (0° latitude) and the Tropic of Cancer (approximately 23.5° N) are parallel circles. By definition, they never intersect. While the Tropic of Cancer does pass through India, the Equator lies entirely south of the country, running through Indonesia, Kenya, Somalia, and Brazil – but not India. India lies between 8°4′ N and 37°6′ N latitudes, and the Tropic of Cancer (23°26′ N) passes through its centre. The southernmost point of mainland India, Kanyakumari, is approximately 870 km north of the Equator. Even the southernmost territory of India, Indira Point in the Andaman & Nicobar Islands, is approximately 750 km north of the Equator. Ujjain is located well north of the Tropic of Cancer, in the state of Madhya Pradesh. For the Equator to meet the Tropic of Cancer at Ujjain, the Equator would have to shift thousands of kilometres north – a geographical impossibility.The historical contextThe minister is correct that Ujjain holds historical significance. Crucially, the choice of Greenwich was not predetermined by geography. Any meridian could have been chosen. Historically, different civilisations adopted their own prime meridians based on culturally significant locations. Ancient Indian texts, such as the Surya Siddhanta, treated Ujjain as a reference meridian. This was part of a common global tradition: the Greeks used Alexandria, Islamic scholars used Baghdad, and the French used Paris as their respective prime meridians. Longitude is an arbitrary reference system – any meridian can serve as the zero line, though the Greenwich meridian has been internationally adopted as the 0-degree standard. There is no inherent geographical privilege attached to any specific longitude.Unlike the Hellenistic reliance on the “Great Year” to align planetary systems, Indian traditions – such as those in the Surya Siddhanta and the works of Aryabhata – focused on ascertaining the mean planetary motions and on using distinct methods to determine latitude and longitude. As scholars such as Amartya Sen have noted, there was an outburst of mathematical insights emanating from India from the fifth to the 12th century. But they also add that nothing develops in geographical isolation. There is substantial evidence that ancient Indian mathematical schools were influenced by, and in turn influenced, exchanges with other cultures and learned from the mathematical reasoning of the Greeks, Romans, Chinese, and Babylonians.Also read: When You Look into the Box, the Cat Winks BackIn the context of cultural exchange in the ancient world, the name of the 11th-century Central Asian scholar al-Biruni (973–1048 CE) recurs frequently. While he accompanied the military campaigns of Mahmud of Ghazni to the Indian subcontinent, his legacy is that of an impartial scholar. Al-Biruni – a polymath and one of the greatest scientists of the Islamic Golden Age – studied Indian astronomical and geographical traditions extensively. He engaged deeply with Indian texts to refine methods for measuring latitude and also advanced methods for calculating longitudinal differences, building on the Indian frameworks he had studied. His monumental work, the Kitab al-Hind (or Tahqiq ma-li-l-Hind), written around 1030 CE, is an 80-chapter, objective Arabic study of Indian culture, science, and philosophy. Based on firsthand observations and Sanskrit texts, it offers a rare, detailed look at medieval India’s caste system, religion, and scientific achievements. Al-Biruni is regarded by many historians of science as a precursor to the European Renaissance, a figure whose empirical rigour, comparative methodology, and commitment to objective observation placed him far ahead of the scientific thought prevailing in Europe at the time. Al-Biruni was a “cultural ambassador” who bridged Islamic and Indian scientific knowledge systems and introduced them to the other side of the world.Conflation of cultural pride with scientific factWhat transforms a historical curiosity into a matter of concern is the conflation of cultural pride with scientific fact. The minister’s assertion about the Equator and the Tropic of Cancer is not a matter of interpretation or perspective; it is demonstrably false. Such claims, made by a cabinet minister responsible for the nation’s education system, risk undermining scientific credibility – not of Ujjain’s rich heritage, but of the government’s commitment to evidence-based discourse. The irony is poignant. An education minister, standing at a conference celebrating Ujjain’s ancient scientific traditions, chose to embellish its legacy with a claim that contradicts basic geography taught in middle school. In doing so, he inadvertently demonstrated why grounding policy in verifiable fact matters – not just for credibility, but for the integrity of the very traditions he sought to honour. Ujjain deserves recognition for its genuine historical contributions to astronomy and timekeeping. It does not need fictional geography to validate its legacy. The Minister would have served both science and culture better by celebrating what is true, rather than asserting what is not.C.P. Rajendran is a geoscientist and a communicator on science, politics, environment, and education.