Air pollution also affected other northern provinces such as Phu Tho, Tuyen Quang, Thai Nguyen, Hai Phong, Hung Yen, Hai Duong, Ninh Binh, and Thai Binh.
Experts have said that this phenomenon is due to the large difference between day and night temperatures which causes a heat paradox and lowers the air quality.
The pollution is said to be much more severe compared to previous times and can badly affect people's health. Children, elderly, pregnant women, and those with respiratory diseases have been advised to not go outside.
