On May 11 , 1998 , India purportedly detonated a thermonuclear bomb in its Operation Shakti tests ( " Shakti-I " , specifically ) . Dr. Samar Mubarakmand , a Pakistani nuclear physicist , asserted that if Shakti-I had been a thermonuclear test , the device had failed to fire . However , Dr. Harold M. Agnew , former director of the Los Alamos National Laboratory , said that India 's assertion of having detonated a staged thermonuclear bomb was believable . India says that their thermonuclear device was tested at a controlled yield of 45 kt because of the close proximity of the Khetolai village at about 5 km , to ensure that the houses in that village do not suffer significant damage . Another cited reason was that radioactivity released from yields significantly more than 45 Kilotons might not have been contained fully . After the Pokhran-II tests , Dr. Rajagopal Chidambaram , former chairman of the Atomic Energy Commission of India said that India has the capability to build thermonuclear bombs of any yield at will
Operation Shakti
Pokhran-II
Thermonuclear weapon