WHO study findings
Air pollution could have killed at least 600,000 Indians in 2012, a study conducted by the World Health Organization.For about a fifth of the 3 million had died worldwide because they were exposed to fine particulate matter (PM2.5) that may have aggravated or been directly responsible for cardiovascular diseases and lung cancer.

What is Particle pollution?
Particle pollution (also called particulate matter or PM) is the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are small enough to be seen with the naked eye. These penetrate into our body and cause various illness.

India’s worldwide ranking/Position 
India comes just behind China — which witnessed an estimated 800,000 deaths — says the study.
It is second among all countries in the absolute number of deaths caused due to exposure to air pollution.

Sources of emissions of fine particulate matter
Industries, households, cars and trucks emit complex air pollutants, including invisible PM2.5 particulates. A lot of the fine particulate matter comes from fuel combustion, both from mobile sources such as vehicles and from stationary sources such as power plants, industry, households or biomass burning.

Types of ailments caused by particulate matter
The impact of fine particulate matter (PM2.5) highlighted by the World Health Organisation (WHO) study is felt through a broad spectrum of acute and chronic illnesses that cause premature death.
These include lung cancer, chronic obstructive pulmonary disease (COPD) and cardiovascular diseases.