Worsening air pollution is choking Bangkok, closing schools. The government is asking people to work from home and avoid outdoor activities.

It is not just in the capital. The country's air quality plummets during this season when the atmosphere is dry and stagnant. The density of the airborne pollutant PM2.5 has been rising nationwide.

Smoke from vehicular emissions and widespread agricultural burning are believed to be major contributors. The Bangkok Metropolitan Administration says more than 300 schools were closed on Friday.

One woman said that even with the sun out, it's cloudy and smoky.

Authorities in Bangkok are introducing measures to curb emissions. They have limited access of heavy vehicles in parts of the capital. Beginning Saturday, they'll also make public transportation free for a week.

Officials say the pollution could ease next week, but they're urging people to take precautions against the smog.