It is very irony to map rails vs roots when Railways saves a tonne for environment compared to road. Rails have more capacity/m compare to road. Though constructing Bangalore suburban requires some tree fell, In long run it saves many. Why no one debating about pollution caused by NICE road, Bangalore Chennai Expressway project, Bangalore mysore expressway project which moves less than 10% of what a normal suburban and heavy rail moves.. If 2 lanes in middle of bangalore mysore expressway taken away even light railway constructed in that space it would move same amount of persons/hour/m than what currently the expressway moving in 2 lanes.