A meeting of the Delhi Cabinet, presided over by Chief Minister Sheila Dikshit, deliberated upon the proposal of the Environment Department but did not take any decision.
Sources said Dikshit asked the Environment Department to specify how it plans to penalise the offenders.
They said the environment department, in its proposal, recommended strict penalty against those who violate norms for checking pollution by their vehicles.
A recent study had shown that air pollution in the city has been increasing significantly.
The proposal sought a series of measures including dedicated air quality monitoring mechanism, specific measures to reduce vehicular emissions, strategies to reduce the number of vehicles on roads, strengthening non-motorised transport network and introducing parking policy.
The sources said at least two ministers had opposed the proposal by the environment department as "tough measures" like enhancing penalty on violators could create a negative impact ahead of the assembly election which is slated for November.
According to the action plan, strict action will be taken against owners of vehicles if the emission levels exceed the permissible limit, especially against those vehicles entering the city from neighbouring states.
It said 121 entry points will be monitored by the traffic police and officials of transport department. If vehicles not bound for Delhi cross the city, they will be turned away.