New Delhi (PTI): Residents of Delhi's Rohini area woke up to the sound of a loud blast on Sunday morning. Its vibrations were felt in faraway houses, hundreds of metres away, they said.

Locals said there was a "chemical-like" smell at the site and thick white smoke everywhere as panic gripped the Paschim Vihar area after the blast happened near a CRPF school.

"It wasn't like a firecracker, the sound was incredibly loud. And for 15-20 minutes, there was just smoke everywhere," said Kiran Sachdeva, a resident of the locality.

Sachdeva, in her 60s, described the blast as an "earthquake-like" shock, and said her house was about 200-250 meters away from the site.

Local businesses were affected by the explosion, with the fire brigade, police, bomb squad as well as a team of the NIA and NSG visiting the area to ascertain the cause of the explosion. No one was injured in the incident but the walls of the schools and some shops and a car nearby received damage, according to officials.

The usually-bustling streets were eerily quiet, with all shops and kiosks closed and their glass windows and signboards shattered.

Himanshu Kohli, a shopkeeper, said when he heard the blast, he ran towards the spot. He said white smoke filled the air and a strong, chemical-like smell emanated from the site.

"Glass windows and boards were broken. I got scared and returned to my shop," Kohli said.

Parents of school-going children, though relieved that it happened on a Sunday, couldn't help but wonder what could have been.

"My son studies in class 9 at that (CRPF) school. I couldn't help but be worried about him," said Rita Singh, another Paschim Vihar resident.

Anita Singh had just returned from the temple when she heard the "very loud explosion".

"I felt the vibrations in my house. It felt like someone's cylinder had exploded nearby. My children's school bus comes here and usually we stand at this (near the school) gate in the morning.

"But since today was Sunday, nobody got hurt. I shudder to think about how big a disaster it could have been if it had happened during the weekdays," she said.

Thirty-five-year-old Anish Malhotra woke up in fear when he heard the explosion.

"When I came outside, it was all smoky, but thankfully it was Sunday, and schools were closed, because there are two schools adjacent to each other here, he said.

Yet, people are wondering about the lingering smell of chemicals, which has heightened tension in the area, Malhotra said.

People also noted that the blast occurred in the festive season -- many are observing Karwa Chauth on Sunday and Diwali is also approaching -- when streets are filled with crowds.

"This road is pretty busy, and if it had happened in the evening, I don't know how much damage could have occurred. Today is Karwa Chauth, and many people would have been out celebrating here," Dhiraj Parana said.

Another local said he did not come out initially when the blast happened. Later when he went out, he saw some early morning shoppers running away.

"It looks like some mischievous activity. My child studies here and now there will always be a fear in my mind that anything can happen at any time," a woman lamented. "I've never witnessed something like this before," another resident said.

Officers of the National Security Guard (NSG), National Investigation Agency and Delhi Police have cordoned off the entire area of the explosion site. They are collecting samples from the area, CCTV footage and other data to ascertain the cause of the blast, which is currently suspected to be a crude bomb, officials said.