Taal Volcano spewed volcanic smog, triggering class suspensions in the Philippines.

Video shows the toxic haze shrouding the volcano and the surrounding lake in Batangas province on August 18.

Local authorities said in-person classes in six towns have been suspended due to the smog. Residents were also urged to stay indoors, or wear face masks when going outside.

Philippine seismological agency PHIVOLCS said in an August 19 bulletin that the sulfur dioxide flux was at 3,355 tonnes per day, with plumes reaching up to 7,900 feet high.

Upwelling of volcanic fluids was also observed.

Taal Volcano is still under Alert Level 1 indicating mild unrest.

The Philippines is an archipelago of more than 7,000 islands inside the Pacific 'Ring of Fire' where the majority of Earth's volcano eruptions and earthquakes happen.