What's more polluting? Euro III Diesel Cars or Paralysed Traffic?

Off late, there's been a lot of hue and cry over increasing number of diesel cars including SUVs on the road owing to subsidised diesel rates, thereby increasing pollution on the road. I feel it is camouflaging the real cause of vehicular pollution, as there shall always be a category of vehicles causing maximum pollution. It maybe a diesel car today (though I am not sure if a new Euro III or Euro IV compliant diesel cars is more polluting than a 5 year old petrol car) or a petrol bike yesterday, but solution is not to phase out a class of vehicles out but look at root of the problem and finding means to nix them.
I think biggest cause of pollution today is delaying trips of vehicles on the road. Every vehicle today has to spend lot more time on the road than it should -owing to short and frequent and even big traffic jams owinng to improper traffic management at work sites, potholed roads awaiting proper repair. Besides, a lot of these vehicles just don't want to be there but has to be because of lack of proper public transport. Government should therefore ensure ways to reduce travel time as well as number of vehicles by aggressively focusing on several factors simultaneously such as:
1. Increasing focus on traffic management at peak hours -which unfortunately is not happening now. Traffic police should seriously consider outsourcing a portion of traffic management in electronic format like using GPS services and ensuring proper manpower at places where there is more congestion.
2. Increasing MRT services: Delhi boasts of a gargantuan fleet of Bluelines yet leaves a lot to be desired. Most of the fleet is ill-managed with little comfort for passengers and add to that mass killing by them everyday thus making it a necessary evil. Government should ensure disciplining the same by ensuring they stick to desired fitness levels, speed limits and bus lanes, imposing grave penalties for breaching these standards for both service providers as well as regulatory bodies i.e. Delhi Traffic Police and continuously invite more competition which shall result in better services.
3. Stricter policies on execution of new projects: Delhi has a long list of infrastructure projects in pipeline for which every government tries to take credit during its regime by large prinnt ads, but none of them has zeroed in on ensuring speedier execution of the same which shall facilitate faster transport and lower pollution levels for the city.
I am sure joint action from government, execution bodies and enforcement agencies will not only speed up projects but also ensure better lifestyles, lower pollution levels and even less time spent on frills like ban on certain class of vehicles, just for sake of pretending to be ON THE JOB.