Several areas in Cavite, Batangas, Laguna and Metro Manila declared suspension of face-to-face classes and work in government offices Friday.

In Metro Manila and nearby provinces, Science and Technology Secretary Renato Solidum said the smog was caused by pollution.

In a report , the Office of Civil Defense said Taal Volcano is producing volcanic fumes which resulted in the presence of Vog or volcanic smog in Batangas and in nearby areas.

As per the Department of Environment and Natural Resources (DENR) Environmental Management Bureau (EMB) and Philippine Atmospheric Geophysical and Astronomical Services Administration (Pagasa), the smog in Metro Manila was due to thermal inversion.

Thermal inversion occurs when particles mix with smoke, pollutants or volcanic aerosols and these are unable to rise. ''A reduction in the smog is expected in the afternoon because of rainshowers,'' said forecaster Rhea Torres in a phone interview with Daily Manila Shimbun.

The Metropolitan Manila Development Authority (MMDA) announced the suspension of the classes in all levels of public and private schools. The MMDA noted that it is "based on the announcement made by the 17 local government units in the National Capital Region (NCR)".

In its Facebook post, Cavite Provincial Disaster Risk Reduction and Management Office (PDRRMO) said suspension of classes in all levels of private and public schools were declared over the areas of Alfonso, Amadeo, Bacoor City, Cavite City, City of Carmona, Dasmarinas City, GMA, Gen. Trias City, Imus City, Indang, Kawit, Magallanes, Maragondon, Mendez, Naic, Noveleta, Rosario, Silang, Tagaytay City, Tanza, Ternate and Trece Martires City.

In Laguna, the cities of San Pedro, Calamba, Cabuyao, Santa Rosa and Binan also suspend classes in all levels of public and private schools.

According to Office of Civil Defense in Calabarzon, the shifting to modular distance learning were implemented in Barigon Elementary School, Mahabang Gulod Elementary School, Bilibinwang Elementary School, Banyaga Elementary and High School in Agoncillo, Batangas, also in the cities and municipalities of Lemery and Calaca while classes in all levels of private and public schools were suspended in Alitagtag, Balayan,, Calatagan, Lian, Nasugbu, Tanauan City, Balete, San Nicolas, Tuy, and in Taal. Robina Asido-Eric Acidre/DMS