The most polluted country in the world is India. The stats are based upon many different elements such as waste on the ground and chemical pollution in the air and also trash and other elements that ruin the environemnt's purity levels. India has 7 of the 10 worst polluted areas with China being a close contender. Where there is pollution, poor health abounds. Because the people are breathing the air, they are subject to such things as respiratory illnesses. They are generally malnourished so Diabetes and other diseases that are based upon eating healthily are running rampant.
Then there are ailments that are plentiful which have to do with living in unsanitary conditions, like bacteria born health issues. With India having so much pollution, it's a wonder that it is still a tourist attraction, but it is.
It is a sad situation to be publicly named as the most polluted country, but I am afraid this is Pakistan. Travellers to the country will know to their cost that garbage and sewage are not properly managed. The land is polluted, and so is the water.
Bottled water is essential for tourists to avoid serious illness, and the normal supply is problematic for the health of residents of Pakistan. Pollution is a problem in this part of Asia. Air pollution affects everyone venturing outside their homes. In Pakistan the measure for PM 2.5 is 115.7 whereas in Australia it is below 6.