India's air quality is worst in the world for its effect on human health, according to a recent study from Yale and Columbia universities, measuring 3.73 out of a possible 100 points. The study, which used satellite data to measure air pollution concentrations, found that the fine particulate matter level in India is nearly five times the limit at which it becomes unsafe for humans. The next worst performer was Bangladesh, at 13.66, with Nepal, Pakistan, and China finishing out the bottom five. The weakest performers worldwide were concentrated in Asia and Africa, while the strongest performers were spread across Europe, North and South America, and North Africa. Particulate matter is a main cause of acute lower respiratory infections, which the World Health Organization found to be one of the most common causes of death among children under five in India. In terms of overall environment, India outperformed only Kuwait, Yemen, South Africa, Kazakhstan, Uzbekistan, Turkmenistan, and Iraq. For the full story, seehttp://india.blogs.nytimes.com/2012/02/01/indias-air-the-worlds-unhealthiest-study-says/. To explore the data from the study, seehttp://epi.yale.edu/dataexplorer/indicatorprofiles?ind=eh.air.