Basanti Dulal Nag Chaudhuri (6 September 1917 – 25 June 2006) was an Indian Nuclear scientist and academic, and Scientific Advisor to the Ministry of Defence, Government of India.

While serving as the Director General (chairman) to the Defence Research and Development Organisation (DRDO), he played influential role in Pokhran-I (Smiling Buddha), India's first successful Nuclear bomb test on 18 May 1974.

This historic achievement made India the sixth nation in the world to become a nuclear superpower, after the United States of America, Soviet Union (now Russia), England, France, and China.

In the early 1970s, as the Scientific Advisor to the Ministry of Defence and chair of the Cabinet Committee on Science and Technology, Basanti Dulal Nagchaudhuri played an influential role in Smiling Buddha, India's first nuclear test.

Basanti Dulal Nag Chaudhuri hailed from a Bengali Hindu family of Narayanganj, Dhaka, Bengal Presidency, British India (present-day Bangladesh).

In Allahabad, he met influential lawyer Parmeshwar Narayan Haksar as well as renowned Indian physicist, Meghnad Saha.

Through Saha, he came in contact with Ernest Lawrence and with the latter's support he moved to the University of California, Berkeley at the end of 1938 to work on his doctorate in Nuclear Physics.

After completing his doctorate in 1941, Nagchaudhuri returned to the Rajabazar Science College, University of Calcutta to join Saha's research group.

[3] Nagchaudhuri's research focused on nuclear isomers, induced radioactivity, Cherenkov radiation and nonthermal plasma.

Before returning to India in 1941, with support from Saha and funding from the Tatas, Nagchaudhuri had arranged for shipment of parts for a cyclotron magnet to the Calcutta University.

[2] Based on Nagchaudhuri's recommendation, Project Valiant was initiated in 1972 to build a liquid-fuelled intermediate range ballistic missile.

[9] While both projects were terminated in 1974 due to conflicts within DRDL and resulting lack of progress, they laid the foundation for the successful Integrated Guided Missile Development Program in the early 1980s.

The committee made several key recommendations about the requirement to patrol India's vast coastline, set up a registry of offshore fishing vessels in order to identify illegal activity, and establish a capable and well-equipped force to intercept vessels engaged in illegal activities.

[6] Nag Chaudhuri maintained an active interest in Hindustani Classical Music and Bengali literature and culture.