In May, coal reserves of the national capital had been reduced to a day.
The National Capital Region may face a blackout as the coal reserves with the Delhi government were only for a-day-and-a-half, said Power Minister Satyendar Jain who has written to Union Power Minister RK Singh regarding the same.
In the letter, Mr Jain informed the minister about the coal supply shortage to the NCR power plants -- Dadri, Jhajjar and Badarpur.
"Since June 19, the coal stock is continuously declining and has reached approximate 90,000 MT on Wednesday, which is only one and a half days requirement," Jain wrote adding that the "situation is extremely critical".
The reason he gave for the shortage is the non-availability of transportation rakes with the railways.
Mr Jain requested Singh to "intervene personally and take up the matter with the Railways for providing rakes on priority for transportation of coal to these power plants to avoid blackout in Delhi".
While addressing the media on Wednesday, Jain said that ideally power plants should have a reserve coal stock for 15 days.
He also said that the power demand was high during this season.
It was the second time in the season that such a warning was issued. In May also, the issue had arisen as the coal reserves of the national capital had been reduced to a day.