Here is your 10-point cheatsheet to this big story:
China's objection, made on technical grounds, came an hour before the deadline, after which the resolution to tag him a "global terrorist" would have been considered adopted by the UN Security Council. In a note sent to the Council, China said it needed more time to examine the sanctions request on Masood Azhar, diplomats said.
The proposal to designate Masood Azhar under the 1267 Al Qaeda Sanctions Committee of the UN Security Council was moved by France, UK and the US on February 27. Germany became a co-sponsor to the proposal later on Wednesday.
A UNSC tag will subject Masood Azhar to assets freeze, travel ban and an arms embargo. An assets freeze under the Sanctions Committee requires that all states freeze without delay the funds and other financial assets or economic resources of designated individuals and entities.
"The 1267 Sanctions Committee, upon completion of the no-objection period on 13 March 2019, wasn't able to come to a decision on the proposal for listing Mohammed Masood Azhar under the UN Sanctions regime, on account of a member placing the proposal on hold," the foreign ministry said in a statement.
"We are disappointed by this outcome. This has prevented action by the international community to designate the leader of Jaish-e-Mohammed (JeM), a proscribed and active terrorist organization which has claimed responsibility for the terrorist attack in Jammu and Kashmir on 14 February 2019," the ministry said.
The UN had banned the Jaish-e Mohammad in 2001. But India's efforts to ban Masood Azhar after the Mumbai terror attack was not successful as China has repeatedly blocked the move, apparently at the behest of Pakistan, its strategic ally.
A veto-wielding member of the UN Security Council, China had blocked the move by India and other member nations three times earlier. The last time China blocked the move was in April 2016, months after the Jaish attack on the Pathankot air base. Registering a strong protest at the time, India said saying such a move, made only on "technical grounds," was "incomprehensible".
Beijing had tipped its hand earlier on Wednesday. "I could reiterate that China will continue to adopt responsible attitude and participate in the deliberations in the UNSC 1267 Committee," Chinese Foreign Ministry spokesman Lu Kang told the media.
The Jaish-e Mohammad, headed by Masood Azhar, has carried out many terror attacks in India; it was involved in the attack on Parliament, the Pathankot air force base and army camps in Jammu and Uri.
Jaish had also claimed responsibility for the February 14 Pulwama suicide attack, which left 40 personnel of the Central Reserve Police Forces dead. Days later, India carried out airstrikes at a Jaish camp in Balakot in Pakistan, which was followed by an aerial dogfight with the Pakistan Air Force, which had targeted Indian military installations.