Northern China, including Beijing and Tianjin, is experiencing heavy smog due to a return to coal-fired power generation to stimulate the economy. Pollution warnings have been issued, affecting around 100 million people in the region. China had previously closed coal-fired power plants and relocated heavy industry to improve air quality for the 2022 Winter Olympics. The recent smog is attributed to increased power consumption in industries like cement and brick, as well as heavy truck exhaust fumes. The expansion of coal-fired generation contradicts China's carbon goals, and new coal mines are being approved despite efforts to develop clean energy.