Smog hangs over Metro Manila as seen from Antipolo City on Monday morning. Experts from PAGASA said the smog was whipped up by thermal inversion, or the presence of warmer air on top of colder air mass near the ground, preventing pollutants from dispersing. PHOTOS BY JOHN ORVEN VERDOTESmog hangs over Metro Manila as seen from Antipolo City on Monday morning. Experts from PAGASA said the smog was whipped up by thermal inversion, or the presence of warmer air on top of colder air mass near the ground, preventing pollutants from dispersing. PHOTOS BY JOHN ORVEN VERDOTESmog hangs over Metro Manila as seen from Antipolo City on Monday morning. Experts from PAGASA said the smog was whipped up by thermal inversion, or the presence of warmer air on top of colder air mass near the ground, preventing pollutants from dispersing. PHOTOS BY JOHN ORVEN VERDOTESmog hangs over Metro Manila as seen from Antipolo City on Monday morning. Experts from PAGASA said the smog was whipped up by thermal inversion, or the presence of warmer air on top of colder air mass near the ground, preventing pollutants from dispersing. PHOTOS BY JOHN ORVEN VERDOTESmog hangs over Metro Manila as seen from Antipolo City on Monday morning. Experts from PAGASA said the smog was whipped up by thermal inversion, or the presence of warmer air on top of colder air mass near the ground, preventing pollutants from dispersing. PHOTOS BY JOHN ORVEN VERDOTESmog hangs over Metro Manila as seen from Antipolo City on Monday morning. Experts from PAGASA said the smog was whipped up by thermal inversion, or the presence of warmer air on top of colder air mass near the ground, preventing pollutants from dispersing. PHOTOS BY JOHN ORVEN VERDOTESmog hangs over Metro Manila as seen from Antipolo City on Monday morning. Experts from PAGASA said the smog was whipped up by thermal inversion, or the presence of warmer air on top of colder air mass near the ground, preventing pollutants from dispersing. PHOTOS BY JOHN ORVEN VERDOTE