The firemen said it was a "challenging operation" since the building had "almost zero ventilation"

Firefighters had to break a window grill on the first floor of a factory that was ravaged by a blaze on Saturday to rescue the trapped workers inside, according to a Delhi Fire Services official.

Located in the narrow lanes of Shahdara's Jhilmil Industrial Area, the hardware factory was functioning without a no-objection certificate (NOC) from the Delhi Fire Services.

The firemen said it was a "challenging operation" since the building had "almost zero ventilation" and had become a "furnace" due to the blaze.

"There was almost no ventilation and the factory was sandwiched between other factories from all sides. There were very few windows in the building and that too, very small ones, while there was no ventilation at the rear of the factory," Delhi Fire Services Director Vipin Kental said.

As there were only a few windows, the smoke was trapped inside the building, making it difficult for the firefighters, he said, adding that the temperature inside the building must have been 250 degrees Celsius.

"We used external ladders to reach the building. The windows had a very strong grill and the firemen had to break the grill of one of the windows using a hammer. They brought out five persons, two of whom survived, while three died," Kental said.

According to a fireman involved in the rescue operation, they broke the window grill on the first floor of the building.

The smoke had engulfed the stairs leading to the second floor, where the workers were trapped, he said.

"The locals told us three persons were trapped inside while two were already taken out," he added.

One of the firemen climbed up the stairs and saw the bodies of two women and a teenage boy near a window. One by one, he brought the bodies of the women out. The body of the teenager was brought out with the help of one of his colleagues, according to the fireman involved in the operation.

He said they "exercise extreme caution" while bringing people out and avoid using external ladders as there is always the danger of people falling from it.

"The fireman brought out two bodies, but by then, he was exhausted due to the heat and smoke. He was joined by another fireman, both of them wore self-contained breathing apparatus, entered the building and brought the third body out," he added.

The rescue operation lasted for 15-20 minutes, Kental said.

One of the firemen, Assistant Divisional Officer Nagendra Sharma, lost balance on the stairs and fell, which resulted in a slipped disc, officials said. Assistant Divisional Officer Rajesh Shukla also suffered a fall but was not hurt. Sharma has been hospitalised.

Talking about the rescue operation, Kental said it was difficult as there was no way big vehicles could enter the narrow lane.

The smaller vehicles entered the lane while the bigger ones were stationed afar for providing water supply to the smaller vehicles, he added.

The fire department is planning to write to the Delhi Disaster Management Authority (DDMA) and urge them to take action against such units since they are flouting norms under the Disaster Management Act.

Two women and a teenager were killed in the massive fire that broke out in the two-storey hardware factory in the morning.

According to the fire officials, the information about the blaze was received at 9.25 am and 31 fire tenders were rushed to the spot. The blaze was brought under control by 2.45 pm while the cooling operations are underway.