Only vehicles purchased prior to Oct. 1, 2007, qualify for a credit.

This guide explains which vehicles qualify to take the tests, what's involved in the tests and how to book them.

Shot-blasting vehicles used to remove paint or other material from the surfaces of bridges, girders and the like do not qualify.

Self-propelled vehicles with one, two or three drums and walk behind rollers qualify in this category.

Other goods and vehicles imported for commercial purposes will not qualify for this particular relief.

These are areas where you may have to pay a daily charge if your vehicle doesn't meet certain emission standards or qualify for an exemption.

What's more, the amendment relaxed the performance standards for clean fuel vehicles to the point that even gasoline-powered vehicles could qualify.

A vehicle constructed or adapted to have a carrying capacity of less than 12 passengers would not normally qualify for input tax deduction.

Not every vehicle or adaptation will qualify for the relief.

Once a certain threshold is met, vehicles may qualify for e1, e2, e3, or e4 levels in the certification program.