New Delhi, March 11 -- The Delhi government on Tuesday said it shortlisted 22 innovations submitted by individuals, researchers and expert institutes to tackle air pollution from the 284 ideas it received as part of the "Innovation Challenge" organised by the government in October last year. Delhi's environment minister Manjinder Singh Sirsa said these 22 ideas will now be prepared for on-ground trials and tested at pollution hotspots. The 22 ideas include 13 solutions focused on controlling vehicular pollution such as vehicle-mounted air purifiers, retrofitted emission-control systems, bio-alkaline exhaust scrubbers. Retrofits have also been shortlisted for buses, trucks and gensets. The remaining nine devices target ambient air, including...