The toxic smog looming over India, more specifically over the nation's capital, New Delhi, poses numerous health and environmental threats. The dangerous conditions have sparked political unrest among citizens, who hope to find a solution.

In New Delhi, air quality has peaked well off the charts for several days at a time, even for over a week, at an Air Quality Index (AQI) significantly over 500. The highest category is listed as "hazardous" at 301-500.

In the United States, the worst AQI is "very unhealthy," which ranges from 201-300. This poor air quality is typically isolated in northwestern valleys, for short periods of time. It occurs during extreme wildfire smoke events, according to AccuWeather Meteorologist Faith Eherts.

Birds sit on electric wires surrounded by smog in New Delhi, India, Wednesday, Nov. 8, 2017. A thick gray haze enveloped India's capital on Wednesday as air pollution hit hazardous levels. (AP Photo/Manish Swarup)

The U.S. has developed a structure to prevent hazardous air quality events of this magnitude from occurring through improvements in policy and regulations.

Air quality in the U.S. was relatively poor prior to the existence of air quality monitoring systems. Cities like New York City, Philadelphia and Pittsburgh would have days of very poor air quality, according to Eherts.

There were short-lived events of poor air quality due to an extended period of calm, dry weather and a lack of industry regulations, Eherts said.

For example, in October 1948, a thick cloud of air pollution formed above the industrial town of Donora, Pennsylvania. The cloud lingered for five days. It killed 20 people and caused sickness in 6,000 of the town’s 14,000 people, an U.S. Environmental Protection Agency (EPA) spokesperson wrote in an email to AccuWeather.

"Events like this alerted us to the dangers that air pollution poses to public health," the EPA spokesperson said.

In this June 3, 2017, file photo, the coal-fired Plant Scherer, one of the nation's top carbon dioxide emitters, stands in the distance in Juliette, Ga. (AP Photo/Branden Camp, File)

The United States has made great strides in decreasing air pollution since its peak.

"In 1970, Congress strengthened the Clean Air Act, created the EPA and gave it the primary role in carrying out the law. Since that time, the EPA, along with states, tribes and local air quality agencies, has made tremendous progress in cleaning our nation’s air," the EPA spokesperson said.

From 1970 to 2016, the combined emissions of six common air pollutants declined 73 percent in the U.S. Meanwhile, the economy grew, the population increased, energy use increased and people drove more, according to the EPA.

The six common air pollutants are fine and coarse particulate matter (PM10 and PM2.5), sulfur dioxide (SO2), nitrogen oxides (NOX), volatile organic compounds (VOCs), carbon monoxide (CO) and lead (Pb).

Since 2000, concentrations of fine particulate matter have declined 35 percent compared to the agency’s annual standard for the pollutant and 45 percent when compared to the 24-hour standard, the EPA stated.

Extremely high levels of particle pollution today are rare. Events such as forest fires can generate high levels of fine particle pollution.

A wildfire burns behind a winery Saturday, Oct. 14, 2017, in Santa Rosa, Calif. (AP Photo/Jae C. Hong)

Air quality hot spots in the U.S., outside of wildfire smoke events, occur mainly in industrious valleys. The valleys of California and the Great Salt Lake Basin in Utah are a few such areas.

These areas are generally dry and are home to industrious cities; therefore, pollutants often get trapped in valleys. This results in periods of poor air quality, Eherts said.

The U.S. continues to monitor and improve air quality through the Clean Air Act, through regulation and by working across all levels of government, including the EPA, states, tribes and local governments.

"Technology developments also have played an important role in this progress by improving pollution control. Industries have helped develop new, innovative and more cost-effective methods to reduce pollution," the EPA spokesperson said.

The Clean Air Act provides broad opportunities for public participation. It encourages open access to data about emissions and concentrations of pollution in the air.

RELATED:
India’s extreme smog pollution can take large toll on human health
AccuWeather air quality blog
4 in 10 Americans live with unhealthy pollution levels in their communities, 2017 'State of the Air' report finds

Aside from a lack of strong policy and regulation in India, there are several other factors that contribute to extreme levels of pollution not seen in the U.S.

One such factor is the climate. There are few places in the U.S. that experience a lengthy dry season comparable to that of northern India.

While the southwestern U.S. experiences a relatively similar climate, this region does not have the expansive industrious economy or widespread agricultural burning practices that the New Delhi region does, according to Eherts.

While the causes of the extreme pollution are well understood, the Indian government has largely failed to find ways to reduce it.

Politics play a large role in this deadlock, according to The Washington Post. Rural farmers and city dwellers are important constituencies for different political parties, and neither side wants to make concessions, according to the report.

There are pollution control laws in India, but enforcement has been lax for fear of alienating critical voting blocs.

However, India is committed to the Paris Climate Accord. While just under two thirds of India's power comes from heavily-polluting coal power plants, it aims for a target of 40 percent renewable energy by 2030, according to CNN.

Report a Typo