The weather department has announced heat wave warning for at least five states as India witnesses its "hottest summer ever" with large parts of the country reporting temperatures around 45 degrees Celsius. The India Meteorological Department (IMD) has predicted heat wave conditions in large parts of the country for at least the next five days. "Rise by about 2 degrees Celsius in maximum temperatures very likely over most parts of Northwest India during next three days and fall by about 2 degrees Celsius thereafter," it said.