Image copyright Reuters Image caption The capital of Indonesia's Riau province, Pekanbaru, has been cloaked in dense haze for weeks

Smoke from huge forest fires in Indonesian has created a cloud of smog over the country, which has spread over neighbouring Malaysia and Singapore.

The fires, which happen every year, are caused by slash-and-burn clearances on the islands of Sumatra and Borneo.

Paper and palm oil companies have been widely blamed for the practice.

Indonesia, which has repeatedly promised to stop the illegal fires, has sent hundreds of military personnel to try to put them out.

It has declared a state of emergency in Riau province, where the haze has been building for several weeks and pollution levels are hazardous to health.

In Malaysia, schools have been closed in the capital, Kuala Lumpur, and several other areas, while Singaporeans are being advised to avoid strenuous activity outdoors.

Image copyright Reuters Image caption Many people have left Pekanbaru but others have struggled on through the haze

Image copyright EPA Image caption Indonesia has sent around 1,000 troops to fight fires in southern Sumatra

Image copyright EPA Image caption It has promised, and failed, to end the seasonal fires many times in the past

Image copyright EPA Image caption Pulp, paper and palm oil companies that own large forest concessions in southern Sumatra are often blamed for illegal fires

Image copyright Reuters Image caption In the Malaysian capital, Kuala Lumpur, there was rooftop swimming under hazy skies

Image copyright EPA Image caption The Malaysian prime minister also had to endure the haze, which enveloped his office building

Image copyright AFP Image caption Most - but not all - Singaporeans stayed indoors, as their Environment Agency raised the pollution index to its highest level in a year

Image copyright Simeon Paterson Image caption Singapore's National Stadium was barely visible from the BBC's studios