Officials in Singapore are urging people to remain indoors amid unprecedented levels of air pollution after a smoky haze caused by forest fires in neighbouring Indonesia worsened dramatically.
Singapore's main measure for air pollution surged to an all-time high and breached a "hazardous" classification that can aggravate respiratory ailments.
Nearby Malaysia has closed 200 schools due to the problem.
Business and flights have not been disrupted in Singapore, but the smog has strained diplomatic ties with Indonesia. Officials in the city-state said Jakarta must do more to halt fires on Sumatra island started by plantation owners and farmers to clear land cheaply.
Singapore's environment minister Vivian Balakrishnan said "no country or corporation has the right to pollute the air at the expense of Singaporeans' health and wellbeing".