Burning trash is spewing toxins into the air. Over 40% of the world's garbage is set on fire every year, according to a published paper in the journal, Environmental Science and Technology.

The polluted air chokes lungs and even makes the sun look less bright. The air, which contains Particulate Matter 2.5 can enter and damage the lungs. The trash burning is also responsible for 5% of manmade emissions of carbon-dioxide.

Lead researcher Christine Wiedinmyer of the government-funded National Center for Atmospheric Research, in Boulder, Colorado, also showed the link between pollution and human disease. Agreeing that it was only the team's first draft, he admitted that there was a "lot of room for improvement in the index." However, at least it did set a direction for the government to make policy decisions.

Governments mostly calculate data collected from incinerators in backyards. However, they do not record trash set fire in other machines at fields and dumps. Collating information regarding population figures, individual trash burning and official reports, researchers have pulled together existing data on population and per capita garbage production, concluding that 41 percent of about 2 billion tons of trash in the world, including plastics, electronic and furniture items are reduced to cinder every year. The maximum trash is burnt by China and India. Some countries like Sri Lanka do not even gather information on the carbon emissions from burning trash.

While laws have not been fully drawn out, even those that are in place are not followed diligently in developing countries. In cold winters, for instance, trash is burnt by those who have no option to fight the cold except to burn the trash to keep warm.

"Reliable estimates are hard to come by in developing countries. To estimate further the proportion of waste burned is pushing the envelope too hard," said Prof. Arun K. Attri, who is associated with the Jawaharlal Nehru University's School of Environmental Sciences.

Yet, there is a consensus that openly burning trash is unhealthy and threatens humanity.