Smiling Buddha (MEA designation: Pokhran-I) was the assigned code name of India’s first nuclear weapon explosion on 18 May 1974. The device was detonated on the army base Rajasthan Pokhran Test Range by the Indian Army under the supervision of several key Indian army personnel.
Pokhran-I was also the first confirmed nuclear test by a nation outside the five permanent members of the United Nations Security Council. Officially, the Indian Ministry of External Affairs (MEA) claimed this test was a “peaceful nuclear explosion”, but it was actually an accelerated nuclear weapons program. The explosive yield is estimated to be around 8kt.

Source: http://en.wikipedia.org/wiki/Smiling_Buddha