The congestion largely affected thousands of office-goers who travel between Delhi and Gurgaon, linked by NH-8, and the traffic helpline was bombarded with calls from distressed commuters.
Dhaulakuan, Kapashera and Mehrauli were some of the areas where traffic crawled for hours and a long tailback stretching over a kilometer was witnessed near the Rajokri flyover around 9 AM, a traffic official said.
After extending the deadline twice, the apex court had on Saturday refused to give more time to cab operators to convert to CNG and put a ban on diesel cabs in the city from May 1.
According to Delhi transport department, about 60,000 taxis are registered in the national capital of which 27,000 run on diesel. Around 2,000 diesel-run taxis had converted into CNG mode in the last two months.