A fresh research by scientists at U.S. National Oceanic & Atmospheric Administration revealed that Nitrous oxide or the so-called "laughing gas" has played a vital role in depleting the ozone layer.

The scientists wrote in the journal Science, "Nitrous oxide emission currently is the single most important ozone-depleting substance emission and is expected to remain the largest throughout the 21st century."

But, scientists also said that ozone could recover in case the emissions of nitrous oxide are restricted.

The study for the first time evaluated nitrous oxide emissions from human activity in terms of their impact on earth's ozone layer.

It may be noted here that apart from natural sources, industrial processes along with byproducts of agricultural fertilization emit Nitrous oxide.

Nitrous oxide, which is also known as laughing gas, is best known as an anesthetic.

U.N.'s 1987 Montreal Protocol led industries to use Nitrous oxide after chlorofluorocarbons or CFCs were banned as CFCs were found to damage ozone layer. Before 1987 CFCs were used in manufacturing refrigerants.

Nitrous oxide stands among greenhouse gases and its emissions are subject to be slashed by 5 per cent below 1990 levels by 2008-2012 as required by the U.N.'s Kyoto Protocol.