More than 95 per cent of the world’s population is breathing unhealthy air, with India and China jointly contributing to over 50 per cent of global deaths attributed to pollution, a new report has found.

According to the annual State of Global Air Report, published on Tuesday by the Boston-based Health Effects Institute (HEI), long-term exposure to air pollution contributed to an estimated 6.1 million deaths across the globe in 2016, reports CNN.

The report found that India topped China for early deaths from outdoor air pollution with 1.1 million in 2016.

While China had made some progress in declining air pollution, India, Pakistan and Bangladesh have experienced the steepest increases in air pollution levels since 2010, it added.

Air pollution was the fourth-highest cause of death among all health risks globally, coming in below high blood pressure, diet and smoking, according to the report.

 Air pollution takes a huge personal toll worldwide, making it difficult to breathe for those with respiratory disease, sending the young and old to hospital, missing school and work, and contributing to early death,’ CNN quoted Bob O’Keefe, vice president of HEI, as saying in a statement on Tuesday.

‘The trends we report show real progress in some parts of the world - but serious challenges remain to eliminate this avoidable affliction,’ he added.

The report also took into account those exposed to the burning of solid fuels in their homes, typically used for cooking or heating their houses, resulting in indoor air pollution.

In 2016, a total of 2.5 billion people—one in three of global citizens— were exposed to air pollution from solid fuels such as wood or charcoal.

Tuesday's report is the latest in a string of studies investigating the effects of air pollution on global populations, CNN reported.

In April 2017, the World Health Organization said that environmental pollutants cost an estimated 1.7 million lives among children under the age of five.

In 2015, nearly one in six deaths, an estimated nine million worldwide, was related to pollution in some form -- air, water, soil, chemical or occupational pollution, according to a study published in The Lancet.