Every year, farmers in Indonesia clear large swaths of forest by setting deliberate slash-and-burn fires, sending clouds of smoke into the atmosphere, choking neighbors, including Malaysia and Singapore. This season has been the harshest in years -- in Singapore yesterday, the Pollutant Standards Index (PSI) rose to the highest level on record, reaching 371, prompting government officials to warn residents to stay indoors, and urging the Indonesian government to take action. Indonesia accused Singapore of acting "like a child", and warned it to stay out of domestic affairs. Singapore's Prime Minister Lee Hsien Loong said the haze could persist for weeks or longer, as the two nations prepare for emergency talks to ease the crisis.