Volcanic smog shrouded a city as Taal Volcano belched gas in the Philippines.

Video shows the toxic haze blanketing Tagaytay City in Batangas province, some 30 miles south of the capital Manila, on August 19.

The volcanic smog or 'vog' reduced visibility, and triggered school suspensions in six nearby towns. Local authorities urged residents to stay indoors, or wear face masks when going outside.

Philippine seismological agency PHIVOLCS said the vog - a combination of acidic sulfur dioxide droplets and water vapour - was still present due to continuous volcanic emissions on August 20.

In a bulletin today, PHIVOLCS said Taal Volcano spewed 8,500-foot-high gas plumes. Upwelling of hot volcanic fluids was also observed at the volcano's main crater.

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.