JAKARTA: Indonesian forest fires that choked a swath of Southeast Asia with a smoky haze for weeks last year may have caused more than 100,000 premature deaths, according to new research that will add to pressure on Indonesia's government to tackle the annual crisis.

The study by scientists from Harvard University and Columbia University to be published in the journal Environmental Research Letters is being welcomed by other researchers and Indonesia's medical profession as an advance in quantifying the suspected serious public health effects of the fires, which are mostly set to clear land for farming. The number of deaths is an estimate derived from a complex analysis that has not yet been validated by analysis of official data on mortality.