India signed an international treaty governing global civil nuclear liability, a step sought by Washington to reassure US suppliers entering the country's fledgling $150 billion atomic power market. It is a very positive step to assure that international standards apply, and US companies will have a level playing field to compete, Undersecretary of State for Political Affairs William Burns told a White House briefing.The signing took place at the headquarters of the UN nuclear watchdog in Vienna, a little over a week before US President Barack Obama visits India, when he will meet US business leaders in Asia's third-largest economy. India's parliament passed legislation in August to open up the domestic nuclear market. But its nuclear liability law also gives the right to seek damages from plant suppliers if there is an accident. India is the only country to have such a provision, which was added after wide political pressure. The United States has pressed India to accede to the multilateral Convention on Supplementary Compensation for Nuclear Damage (CSC) to assure its suppliers any liabilities would be in line with international norms. The CSC which dates back to September 1997 seeks to establish a uniform global legal regime for the compensation of victims in the event of a nuclear accident. India hopes that signing the convention will allay some of the concerns of US companies about New Delhi's own recently-passed nuclear liability law which gives the right to seek damages from plant suppliers if there is an accident.