09 APRIL 2013 - BANTHI, LAMPHUN, THAILAND: A sign put up by the Thai government urges people not to burn the grass in their fields this year. The "burning season," which roughly goes from late February to late April, is when farmers in northern Thailand burn the dead grass and last year's stubble out of their fields. The burning creates clouds of smoke that causes breathing problems, reduces visibility and contributes to global warming. The Thai government has banned the burning and is making an effort to control it, but the farmers think it replenishes their soil (they use the ash as fertilizer) and it's cheaper than ploughing the weeds under. PHOTO BY JACK KURTZ