Thick haze shrouded Manila and nearby cities in the Philippines as a 'thermal inversion' phenomenon kept pollutants near the ground from dispersing.

The smog hung over the capital city and neighbouring areas, including Antipolo City, sparking health concerns among residents this week.

Footage shows the mist covering skyscrapers usually visible from Antipolo City on September 10. The haze was also seen darkening skies over the Metro Manila Skyway on September 9.

Ana Clauren-Jorda, a specialist at state weather agency PAGASA, said the smog was caused by a temperature inversion, which can occur during the country's monsoon season.

She said: 'When we have temperature inversion, a layer of warm air traps cooler air below. That trapped air contains aerosols.'

Aerosols are tiny particles suspended in air that are harmful when inhaled. During a temperature inversion, they accumulate near the ground, unable to disperse due to the warm air mass preventing the layer below from flowing upward.

Ana said: 'People can inhale the pollutants in the air, which are close to the ground because of that inversion. Those with respiratory problems can get sick.'

Locals have been advised to wear face masks when going outside.

PAGASA said the haze is expected to last for several days before dissipating.