Pollution is a problem that most countries around the world have. But few places have the issues of Delhi, India.
Delhi has a metropolitan population of around 26 million, making it the second largest population centre in the world's second most populous country. (The biggest population? That's China.) That's a lot of people that are sadly experiencing a lot of pollution.
All last week, the city was covered in a thick blanket of smog. Flights were being cancelled because the planes could not see well enough to land. And this wasn't just a bunch of low-laying clouds. This was pollution.
A problem that keeps getting worse
The numbers are not pretty. Air quality readings in Delhi last week measured over 900 in some places. What does that mean? These readings measure the amount of fine particulate matter, or PM 2.5, per cubic metre. Fine particulate matter is so small that it can pass through the lungs and into the organs, causing health problems.
So that reading of 900? According to the World Health Organization (WHO), anything over 25 is harmful. This means that the air in Delhi is over 35 times the acceptable healthy limit. Some experts are saying that it equals the effects of smoking 45 cigarettes a day (yikes!).
Little way to escape
Many people in Delhi are afraid to go outside because of the pollution. Normally healthy people are complaining of trouble breathing, having itchy throats, and coughing. When people do go outside, many are wearing scarves to try and protect themselves.
How is Delhi responding? Last week, the city banned trucks coming into the city and suspended construction projects. It even cancelled school last Wednesday to try and keep kids out of harm's way.
But critics complain that these measures are not addressing the problem. For years now, Delhi has experienced severe pollution in the winter. This is a time when nearby farmers begin burning fields to make way for new crops. As this drifts toward the city, high humidity and a lack of coastal winds keep the pollution locked over Delhi. This adds to the already high amount of traffic and fossil fuel factories in the area, creating a health crisis.
What can be done?
Pollution can have many causes, but there are several solutions. For example, parts of China have had some success by cracking down on cars and steel production, and switching from coal to renewable energy. China is a country that, like India, has a very high population and many cities on the most-polluted list.
But while some major Chinese cities like Beijing are a bit cleaner now, they are still not all that clean. And despite real strides in green energy, China is still wrestling with how to leave pollutants like coal behind. Unfortunately, India is even further behind them.
Activists hope that yet another winter of dangerously dirty air in Delhi will make the public say enough is enough and demand change.