Schools and colleges will be shut in Mumbai on Thursday given a forecast for heavy rainfall in the city and its neighbouring areas, the Brihanmumbai Corporation announced this evening. The India Meteorological Department (IMD) has upgraded its ‘orange alert’ to a ‘red alert’ for Mumbai, Raigad, Ratnagiri and Sindhudurg districts. Meanwhile, an ‘orange alert’ remains for Palghar and Thane.