Seoul: China on Friday continued to oppose India's entry to the NSG, saying the global non-proliferation order will collapse if New Delhi joined the group without being a signatory to the NPT.
Beijing reiterated that accepting the Non Proliferation Treaty was a must for India to become a member of the elite 48-nation club which regulates global nuclear trade.
China said although it understood that India wanted to use nuclear energy to generate clean power, other countries had similar needs.
"If exceptions are allowed here or there on the question of NPT, the international non-proliferation order will collapse altogether," Wang Qun, Director General of the Department of Arms Control of China's Foreign Ministry, said in a statement here.
"NPT is a must. In other words, the applicant state shall be party to the NPT.
"This is a rule not set by China but reaffirmed by the international community. NPT represents the cornerstone of the entire non-proliferation regime," Wang added.
"In the absence of NPT as a political and legal basis, it will be inconceivable for the JCPOA (Joint Comprehensive Plan of Action or the Iran nuclear deal) to be reached.
"And moreover, it will add huge difficulty to implement JCPOA. And in the absence of NPT as the political and legal basis, how could the nuclear issue on the Korean Peninsula be resolved?
"All these merit reflection. While it's easy to adopt double standards, the consequence can be enormous," Wang added.
His comments come as the Nuclear Suppliers Group (NSG) held a second day of its plenary in the South Korean capital where India's membership was taken up.
On Thursday, Japan raised the Indian issue. It was taken up at a special session though China had said that the membership of non-NPT countries would not be discussed at the plenary.