China’s major cities are known, in part, for their pollution. As the world’s most populous country, with 1.36 billion people, there are tons of cars clogging the streets and clouding the air. Also contributing to that pollution is the cigarette smoke so many Chinese exhale each day. Smoking is also wildly popular in the country; one of every three cigarettes smoked in the world is smoked in China, according to the World Health Organization (WHO), and a person dies of tobacco use every 30 seconds.

In hopes of lowering smoking rates throughout the country — which currently stand at 300 million people — China Central Television, aka CCTV, aired an anti-smoking ad showing various clips of blackened lungs last week. According to the Daily Mail, the captions in the video below read: “Over 80 percent of lung cancer cases are believed to be caused by long-term smoking or secondhand smoke. … In the images, the lung of someone who has smoked for 15 years is covered with large black spots, while the lung of a 30-year smoker is even more of a ghastly sight, where even the inside is covered with cancer causing substances.”

Cigarette smoke contains over 7,000 chemicals, 69 of which are known to cause cancer, according to the American Lung Association. Eighty percent of the one billion smokers worldwide live in low- and middle-income countries, where tobacco marketing has faced fewer regulations. According to WHO, people in these countries are also less likely to know of the health risks smoking presents — in China, for example, a 2009 survey found only 38 percent of smokers knew smoking causes coronary heart disease, while only 27 percent knew it causes stroke. WHO says picture warnings, such as the ones aired on CCTV, are effective in curbing cigarette use among the most vulnerable populations: children.