Context

According to a latest Indian study published in a leading international journal, over one lakh deaths in 29 Indian cities may be attributed to the rising PM 2.5 levels.

About the Report:

• The study titled Cause and Age, Specific Premature Mortality Attributable to PM 2.5 Exposure: An Analysis for Million Plus Cities is modelled on the basis of the 2015 Global Burden of Disease report.
• This paper has used the 2016 data for the 29 cities as that is the latest year for which the registered all-cause death data is available from the Civil Registration System.

Key-highlights of the Study:

• Delhi tops the list of 29 cities with a million-plus population.
• The study adds that Ischemic Heart Disease (IHD) is the leading cause of death accounting for 58% of the PM 2.5 related premature deaths.
• The most affected are children under the age of five and the 'productive age group' of 25-50 years.

• Exposure to an air pollutant or combination of air pollutants such as PM2.5, NO2 or ozone is associated with an increased incidence of diseases, including Ischaemic Heart Disease, Chronic Obstructive Pulmonary Disease, lung cancer, lower respiratory infections, premature birth (preterm birth), type II diabetes, stroke and asthma. 
• Pre-mature mortality rates due to Lower Respiratory Infection (LRI) in children and Chronic Obstructive Pulmonary Disease (COPD) in adults is substantially higher in the Indo-Gangetic plain where PM 2.5 levels are very high.
• The study also observes that if action is taken rapidly to tackle air pollution, there could be 18% reduction in premature mortality if cities were to attain the National Ambient Air Quality Standards (NAAQS) and a 70% reduction if the WHO standards of PM 2.5 are adhered to.
  
  

Current situation of pollution in India:

• According to the World Health Organisation, nine of the 10 most-polluted cities are in India.
• The status in rural areas is not any better as homes are sites of air pollution due to poor ventilation.
• Furthermore, surface and groundwater sources, and also the soil in many places are extensively contaminated, especially due to pesticide and fertiliser pollution.
• In India, air pollution is the third-highest cause of death among all health risks, ranking just above smoking.

Major Pollutant:

• PM 2.5:
• PM 2.5, an atmospheric particulate matter of diameter of fewer than 2.5 micrometres, affects more people than any other pollutant. 
• Major components: sulfate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water.
• WHO sets recommended limits for health-harmful concentrations of key air pollution both outdoors and inside buildings and homes, based on a global synthesis of scientific evidence. 
• WHO Air Quality Guideline values:

• Ozone:
  • Ozone pollution is a kind of oxide. 
  • The rays of extremely hot sunlight by responding to the smoke from the vehicles make the ozone pollutant. 
  • In addition to the smoke coming out of the vehicles, ozone pollution is also produced from the burning of garbage or smoke from the industries.
• NO₂:
  • Nitrogen dioxide (NO2), a byproduct of fossil fuel combustion in vehicles and power plants, and ozone, respectively, contribute to the formation of photochemical smog, which can have significant impacts on human health.

In India, air pollution is a major environmental risk to health and a top risk factor responsible for the reduced longevity. The government should urgently form a plan to reduce emissions of the harmful gas. Such planning can lead to substantial gains in life expectancy, and reduction in other well-recognized threats to public health.