On this day, 64 years ago, July 31, 1961 (June 19, 1961 in the lunar calendar), sulfur dioxide was the cause of asthma in Yasukai City, Japan. "Yasukhishi asthma" is synonymous with a famous smog incident in Japan. The Yasukhishi asthma incident in Japan is one of the world's famous public hazards and occurred in Yasukhishi City on the eastern coast of Japan in 1961. Since 1955, the city has built three petrochemical complex enterprises one after another, and is crowded with more than ten major petrochemical factories and more than 100 small and medium-sized enterprises around it. Exhaust gases from petroleum smelting and industrial fuels seriously pollute urban air. In 1961, Yokkaichi City suffered a major asthma attack. There is a city of Shikaka on the corner of Ise Bay on the eastern coast of Japan, with an original population of 250,000, mainly textile workers. Because Yokka-City is close to the river, has convenient transportation, and is the gate to the Keihama Industrial Zone, Japanese monopoly capital took a fancy to Yokka-City as a good place to develop the petroleum industry. In 1955, it used the former site of the old naval fuel plant in the Shiohama area before the war. The first refinery was built. After 1958, it became an important coastal industrial area for one-quarter of Japan's oil industry. The main part of the city's industry is a joint venture in the Shiohama area and Wuqi area. Noon-up area An industrial area formed by reclamation in the northern part of Yokkaichi City, with power plants and Noon-up joint ventures. Around these three major oil conglomerates, more than 10 large factories such as Mitsubishi Petrochemicals and more than 100 small and medium-sized enterprises are crowded. As a result, Yotsuki City became a city with serious pollution caused by noise, foul water and smog. Since 1955, yellow smoke has filled the entire city all year round due to the exhaust gas generated by petroleum smelting and industrial fuels (high-sulfur heavy oils). In 1961, the annual emissions of dust and sulfur dioxide from factories in the city reached 130,000 tons. The concentration of sulfur dioxide in the atmosphere exceeds the standard by 5-6 times. A variety of toxic gases and toxic heavy metal dust such as aluminum, manganese and cobalt float in the 500-meter-thick smoke above Yokkaichi City. Heavy metal particles and sulfur dioxide formed sulfuric acid smoke, which caused asthma attacks among citizens. In 1964, the smoke did not disperse for three consecutive days, and asthma patients began to die. In 1957, some patients could not bear the pain and committed suicide. In 1972, a total of 817 asthma patients were confirmed in the city, and more than 10 people died. Later, due to the widespread burning of high-sulfur heavy oil in major cities in Japan, asthma in Yokkaichi City spread across the country. Asthma is spreading in dozens of cities such as Chiba, Kawasaki, Yokohama, Nagoya, Mizushima, Iwakuni, and Oita. According to statistics from the Japan Environment Agency, as of 1972, there were as many as 6376 patients suffering from asthma in Yokkaichi City across Japan.