MUMBAI, Dec. 1 -- Despite repeated claims that construction dust is the largest contributor to Mumbai's worsening air quality, little has been done to curb the menace. Fresh concerns have now emerged over Metro Line 4 works along LBS Marg in Mulund, where unchecked debris and dust continue to choke the area. BJP MLA Mihir Kotecha has alleged that at least 100 spots along the Wadala-Kasarvadavali corridor are actively adding to the suburb's poor Air Quality Index (AQI), owing to unchecked debris, dust and poor housekeeping. Kotecha, who inspected a 2-km stretch of LBS Road on Saturday along with officials from the Mumbai Metropolitan Region Development Authority (MMRDA) and the BMC's T-ward, said that large heaps of scrap, cement blocks, soil, sand and construction waste have been lying unattended for four to five months. "These sites have effectively become dumping yards. Footpaths are broken, debris is everywhere and housekeeping is completely absent. There are 100 such locations in Mulund alone," he said, adding that he has sought immediate corrective action. The MLA also pointed out extensive gaps in basic safety and dust-control protocols. Sources present during the inspection said more than 50% of the locations lacked proper barricading. "The contractor has a Rs.500-crore contract, yet there is no visible expenditure on debris removal or reinstatement of footpaths," Kotecha claimed. Mulund recorded a 'poor' AQI of 260 on 26 November and 256 the following day. Officials who reviewed the data said that dust and waste generated from Metro-4 construction activity appeared to be the largest contributors to the spike. In November, Mulund saw 'moderate' air quality on 11 out of 30 days and 'poor' air quality on two days; data was unavailable for eight days. Kotecha said MMRDA commissioner Sanjay Mukherjee has assured him that the sites will be cleaned and restored within eight days, and that action will be taken against the contractor. The MMRDA did not issue a comment....