'Smiling Buddha' was a near failure, claims US cable

The first nuclear weapon test carried out by India in 1974 was a "near failure", claimed a secret US assessment made in 1996, but it does not explain the reasons for it to arrive at such a conclusion.
The National Security Archive (NSA), which obtained these documents from the State Department under the Freedom of Information Act and made it public yesterday, noted that such an assertion by the US intelligence community may be a reference to the very low explosive yield of the 1974 nuclear tests.
The nuclear tests codenamed 'Operation Smiling Buddha', tested a thermonuclear device in the Pokhran firing range in Rajasthan. Though the yield of the device is debated since then, it is believed that the actual yield was around 8-12 Kilotons of TNT.

The intelligence assessment dated January 24, 1996 also revealed that it was the Indian scientific community who was pushing the then Prime Minister, Narasimha Rao, for another nuclear test.
"Rao's scientists may be pushing for one or more tests of India's unproven nuclear design, which probably needed significant reworking after the near 'failure' of the 1974 test," the intelligence assessment said without giving any further explanation of the reasons for such a conclusion.
The Federation of American Scientists (FAS) on its website claimed that the nuclear tests conducted by India on May 18, 1974 may have only been partially successful.

"The device was placed in a vertical shaft and detonated at a depth of 107 meters. It is reported that the American intelligence community estimated that the actual yield was in the range of 4 to 6 kilotons. The test produced a crater with a radius variously reported at between 47 and 75 meters, and a depth of about 10 meters," FAS says.
"High-resolution commercial satellite imagery discloses that the subsidence area proper has a radius of about 60 meters, and is surrounded by a distinctive heart-shaped perimeter with a radius of roughly 80 meters," it said.