Hundreds of fires continued to burn in northwestern India in early November 2012, covering the region with a gray haze. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image on November 9, 2012. Most of the fires, which are indicated by red “hotspots”, are burning in the state of Punjab. Although the state covers less than 2% of India’s land surface, it produces about one-fifth of the country's wheat. In this region, November is the season for planting wheat and vegetables. In preparation for planting, farmers often set fire to the fields to clear away old crops, fertilize the soil and control pests. Fire has advantages as a readily available and inexpensive tool to manage land, but it has negative effects as well. The pollution brought about by smoke is one of the most widespread detrimental effects of agricultural fires. Not only does smoke irritate lungs, making it hard for the local people and animals to breathe, but smoke can be carried long distances by wind, and air inversions or topography can trap the polluted air in valleys or at the foothills of mountains. In this image, the fires can be seen densely clustered in northwest India, as far as the border with Pakistan, which serves as a break for the fires. Beyond the border, only a few fires are scattered across Pakistan. A thick river of smoke rises from the fires and flows eastward along the foothills of the Himalaya Mountains, and also southwestward, where it covers the green Indus Valley.