In 1978, India knew Pak was 2-3 yrs away from nuclear bomb

Washington, Jul 28 (PTI) Though the US and the UK did
not inform India of a covert operation to stop Pakistan going
nuclear, New Delhi had its own intelligence in 1978 to
conclude that Islamabad was just two or three years away from
making an atomic bomb, according to declassified documents.
Both the US and Britain collectively decided not to
inform India about the operation, fearing it would have
adverse impact in Pakistan if was leaked from New Delhi.
"Having heard reports that an evolving plan to curb
the Pakistani nuclear programme might involve informing the
Indian government about US concerns, (US) Ambassador (to
Pakistan, Arthur) Hummel suggested that going through with
that, especially providing factual information, would have an
adverse impact in Pakistan if word of it leaked from New
Delhi," said the US Embassy cable issued from New Delhi on
November 17, 1978.
Hummel was not worried about leaks from the Nuclear
Suppliers Group but "for USG to be seen by Pakistan to be
colluding with India in this is [a] totally different matter",
said the latest declassified State Department cables.
In response, the State Department said that its
officials had instructions not to share US "concerns" with the
Indians while the then US Ambassador to India Robert Francis
Goheen observed that the Indian government "has known for some
time that we believe Pakistan to be bent on achieving a
nuclear weapons capability."
While he believed that the embassy had offered "no
factual information," he said that Indian diplomat V Shankar
had claimed that Pakistan was "two or three years" away from a
nuclear capability.
Apparently Goheen had asked the CIA station to
investigate where Shankar might have got this information, but
it had "drawn a blank."
According to another cable of September 23, 1978, a
source at the French White House, the Palais de l'Élysée,
informed the US embassy that new information suggested that
Pakistan was determined to complete the reprocessing plant "on
its own."
To acquire the necessary technology, Pakistan had made
"probes in Rome, Tokyo and Madrid" and perhaps elsewhere.
The source suggested that Pakistani might be trying to
develop a nuclear capability so that it could resist
"blackmail" from India but not testing a device so that it
could avoid an "international outcry", the cable said. PTI LKJ
SSB