Deputy government spokeswoman Lalida Persvivatana said the Pollution Control Department (PCD)'s Air Pollution Situation Communication Center has issued an alert on increases of PM2.5 concentrations, particularly in Bangkok, its surrounding provinces, the upper Central Plains and the Northeast.

Lalida attributed the rise to stagnant air and low ventilation rates, causing pollutants to accumulate and disperse poorly.

She said that the Government has instructed the PCD to work closely with provincial authorities to strengthen communication and coordination in tightening controls on pollution sources. They were also told to enforce bans on open burning during this time.