Context: Recently, the U.S. State Department, in its report, has said that China may have secretly set off low-level underground nuclear test explosions despite claiming to observe an international pact banning such blasts, a development that could fuel U.S.-Chinese tensions.

Key Points

• It  has said that the concerns about Beijing’s possible breaches of a “zero yield” standard for test blasts have been prompted by activities at China’s Lop Nur nuclear test site throughout 2019.
• China’s possible preparation to operate its Lop Nur test site year-round, its use of explosive containment chambers, extensive excavation activities at Lop Nur and a lack of transparency on its nuclear testing activities have raised concerns regarding its adherence to the zero yield standard, the report said, without providing evidence of a low-yield test.
• Beijing’s lack of transparency included blocking data transmissions from sensors linked to a monitoring centre operated by the international agency that verifies compliance with Comprehensive Test Ban Treaty (CTBT) banning nuclear test explosions.

About Comprehensive Test Ban Treaty (CTBT) 

• It is a multilateral treaty that bans all nuclear explosions, for both civilian and military purposes, in all environments.
• It was adopted by the United Nations General Assembly on 10 September 1996 but has not entered into force, as eight specific nations have not ratified the treaty.
• The treaty was opened for signature in September 1996, and has been signed by 184 nations and ratified by 168.
• The treaty cannot enter into force until it is ratified by 44 specific nations, eight of which have yet to do so: China, India, Pakistan, North Korea, Israel, Iran, Egypt, and the United States. The U.S. Senate voted against CTBT ratification in 1999.
• Hence, India is a non-signatory member to the treaty.
• In order to verify compliance with its provisions, the treaty establishes a global network of monitoring facilities and allows for on-site inspections of suspicious events.
• Russia, France and Britain – three of the world’s five internationally recognized nuclear powers – signed and ratified the Comprehensive Test Ban Treaty, which still requires ratification by 44 countries to become international law.
• Because both China and the United States are among eight signatories that have not ratified it. But, China has declared its adherence to its terms. Even the United States has observed a unilateral testing moratorium since 1992.
• About ‘Zero yield’: Zero yield refers to a nuclear test in which there is no explosive chain reaction of the type ignited by the detonation of a nuclear warhead.

India and CTBT:

India finds CTBT a threat to national security because of its –

• Discriminatory in nature as US which has already conducted more than 2000 tests suddenly realizes that here was no need to test nuclear devices any more.
• No time-bound disarmament schedule for nuclear weapon states
• CTBT would not help towards nuclear disarmament since it only banned nuclear explosive testing, but not other activities related to nuclear weapons, such as sub-critical (non-nuclear explosive) experiments, or computer simulations

About New START Treaty

• The Treaty between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms is also known as the New START Treaty. 
• New START restricted the United States and Russia to deploying no more than 1,550 nuclear warheads, the lowest level in decades, and limited the land- and submarine-based missiles and bombers that deliver them. 
• The Treaty’s duration is ten years, unless superseded by a subsequent agreement. New START Treaty, entered into force on February 5, 2011 is due to expire in February, 2021.
• A senior U.S. official said the concerns about China’s testing activities supported US President Trump’s case for getting China to join the United States and Russia in talks on an arms control accord to replace the 2010 New START treaty between Washington and Moscow that expires in February 2021.