Mumbai, March 11 -- The onset of summer and a spike in temperatures due to the ongoing heatwave have brought about a sharp rise in forest fires in the Mumbai Metropolitan Region (MMR). At least four incidents of forest fires were reported from different parts of the city this week alone, as the maximum temperature touched 40 degrees Celsius. On Monday evening, fires were reported in the hillock near Tata Power off Chembur, and the hillocks behind Hiranandani Complex in Powai. Another fire was reported in the same area in Powai on Tuesday, around 1.45pm, affecting over 4,000 square feet; the fire was extinguished by 4pm, fire brigade officials said. The largest fire, at the Aarey forest near Film City, was reported around 3am on Tuesday. Spread over 2 kilometres, the fire was extinguished 12 hours later with the help of 10 fire engines, fire brigade officials said. Dinesh Habbale, Aarey resident and founder of the Adivasi Hakka Sanvardhan Samiti, attributed fires in the area to carelessness by labourers on large film sets in Film City. "A large number of labourers who throw lit bidi or cigarette butts do not realise the consequences. When the butts come in contact with dry grass under high temperatures, the fire spreads very quickly," Habbale said. "We have been constantly fighting fires in different parts of Thane and Tungareshwar over the last couple of days," Pradip Patil, deputy director (north), Sanjay Gandhi National Park (SGNP), told Hindustan Times. Patil suspected "deliberate mischief" was at play in such incidents as most fires were reported from above the fire line - a strip of land cleared of all combustible vegetation and debris to stop the spread of forest fires. "There are many encroachments in the forest and there is much friction between the forest department and forest dwellers due to pending claims under the Forest Rights Act (FRA)," Patil said. Kandivali-based activist Nitin Jha also suspected that forest fires were attempts to clear the forest for illegal encroachment activities. "Forest fires impact air quality, wildlife and forest biodiversity. A thorough investigation must be conducted," Jha said. Debi Goenka from the nonprofit Conservation Action Trust blamed the disconnect between the forest department and communities living in the forest for rising instances of forest fires. "Earlier, local communities would keep an eye, alert authorities and also help douse forest fires which is clearly not happening now," said Goenka....