Air quality affects house prices — Analysis based on RD of the Huai River policy

•Huai River policy leads to higher concentrations of air pollutants and lower house prices in cities north of the Huai River than in the south.•Air quality significantly affects house prices, such as, for every 1 unit increase in PM10 concentration, house prices will decrease by 0.24%; for every 1 unit increase in PM2.5 concentration, house prices will decrease by 0.37%; and for every 1 unit increase in concentration, house prices will decrease by 0.24%.•Huai River policy reduces the air quality in the northern region, and then has a restraining effect on the northern house prices level, and there is no alternative path for the Huai River policy to have an effect on house prices.