Despite making progress addressing some of the world’s environmental issues, other problems such as toxic air have worsened considerably, as shown in a global scorecard created by the Environmental Protection Index (EPI).

According to the EPI’s findings, air pollution has become a growing global problem , particularly in countries with rapidly developing economies such as China and India. More than half of the world’s population, which amounts to over 3.5 billion people, live in a nation where the average exposure to air pollutants exceeds the levels found safe by the World Health Organization (WHO).

Air pollution has worsened so much over time that it is now attributed to 10 percent of all deaths , according to a release from Yale.

People living in East Asia and the Pacific region make up about one-third, or 1.3 billion, of those exposed to to air pollutants, reports the EPI. In India and Nepal, the percentage is almost 75 percent.

Just last month Beijing was swallowed by its worst smog of the year due to particulate matter measured at extremely dangerous levels. Many of the Chinese capital's iconic landmarks disappeared behind the thick haze, including Tiananmen Square and Beijing National Stadium.

(MORE: Pollution Unequally Affects Latinos, Immigrant Communities, Study Says )

In a contrast to those exposed to toxic air, the number of people lacking clean drinking water has been cut nearly in half from 960 million people in 2000 to 550 million today, which is about 8 percent of the world's population.

“We like to call it the tale of two indicators,” EPI report author Angel Hsu told CityLab . “Over the past decade the global community has achieved success in reducing the number of people dying from unsafe water, but we have not been achieving those same results in air pollution. Air pollution has gotten worse and more people are dying from air pollution.”

<img class="styles__noscript__2rw2y" src="https://dsx.weather.com//util/image/w/figure-2-web1400-.jpg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0" srcset="https://dsx.weather.com//util/image/w/figure-2-web1400-.jpg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 400w, https://dsx.weather.com//util/image/w/figure-2-web1400-.jpg?v=ap&w=980&h=551&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 800w" > (Environmental Performance Index)

"The EPI sends a clear signal to policymakers on the state of their environment and equips them with the data to develop fine-tuned solutions to the pressing challenges we face," co-author Kim Samuel told the Huffington Post . "With the very survival of the planet at stake, we hope leaders will be inspired to act - especially in urban areas where an increasing majority of the world's population lives."

The findings from the EPI underscore the need for better environmental measurement and indicator systems. Without them, attempts to manage the environment will suffer and lead to the decline of natural systems and human health.

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