"SMC has implemented its decision to impose green tax on vehicles registered in other states from today," Commissioner SMC M P Sood said.
Barriers have been set up at four locations at Tara Devi, Totu, Mehli and Dhalli to collect the green tax, expected to raise Rs 6.01 crore annually.
The tax for a two-wheeler would be Rs 100 per entry, Rs 200 for light motor vehicles, Rs 300 for utility vehicles and Rs 500 for truck.
An entry permit - valid for a week - would be issued to vehicle owners.
The green tax has been imposed on the pattern of Manali Municipal Council which was earning more than Rs 2 crore annually from the tax.