New Delhi, Jan 1 : India and Pakistan exchanged lists of nuclear installations and facilities, covered under the Agreement on the Prohibition of Attack against nuclear Installations and facilities between both the countries. The Minister of External Affairs said that the Agreement, which was signed on December 31, 1988 and entered into force on January 27, 1991 provides, inter alia, that India and Pakistan inform each other of the nuclear installations and facilities to be covered under the Agreement on the first of January of every calendar year. This is the 31st consecutive exchange of such lists between the two countries, the first one having taken place on January 1, 1992. Pakistan has five operable reactors, with a further unit under construction, with China's help. Pakistan's nuclear weapons capabilities have arisen independently of its civil nuclear fuel cycle, using indigenous uranium. Pakistan is outside the Nuclear Non-Proliferation Treaty due to its weapons programme. Because of it, Pakistan is largely excluded from trade in nuclear plants or materials, which hinders its development of civil nuclear energy. Amid this, China is positively cooperating with Pakistan's nuclear ambition. Pakistan, as of date, has a nuclear weapons stockpile of approximately 165 warheads, according to The Arms Control Association, a neutral membership group located in the US. /IANS