The hot debate among China's top legislators over a draft law on vehicle taxation highlighted two of the most pressing challenges that the country faces - energy conservation and bridging wealth gap.

It was reported that, after the draft law was reviewed by the Standing Committee of the 11th National People's Congress, as a green legislation that intends to tax cars according to their engine sizes, some top lawmakers argued that the levy should be charged in line with the value of cars.

With nearly 200 million motor vehicles on our roads, Chinese legislators have ample reasons to put in place a new law that can effectively promote energy conservation or the use of clean energy vehicles among domestic car-drivers.

China surpassed the United States to become the world's largest auto market in 2009, and Chinese consumers are expected to buy more than 17 million new cars this year, which will place even more pressure on the country's environment and energy supply.

Under such circumstance, Chinese lawmakers are obligated to replace the current law, that taxes vehicles according to the number of passengers they are allowed to carry, with a new green one that will cut taxes on fuel efficient, clean energy vehicles while imposing increasing taxes based on engine capacity. However, it is not unreasonable for some lawmakers to suggest the new tax be based on the value of a vehicle.

The logic is obvious, such an ad valorem tax will help narrow the country's income disparity by taxing those with a multi-million-yuan luxury sedan significantly more than those with cheaper car of the same engine capacity.

Given that the country has made it a key task to pursue inclusive growth in the coming years, legislators are more than willing to do their bit in addressing the widening income gap.

The concerns of lawmakers who give top priority to going green are as justified as the concerns of those who attach greater importance to reducing income inequality.

However, when it comes to a new tax law to regulate the explosive growth of car ownership in this country, top legislators should get their priorities right by focusing on addressing the dire consequences of the rampant growth of car ownership. Not that the need to go green is more important in the long run than the necessity to cut income disparity. The underlying reason why the latest legislation should be made part of a national drive to go green, is that, unchecked the surge in car ownership has become the leading menace to the nation's efforts to reduce pollution and oil dependence.