Sporadic fires in different patches of forests in the past couple of days in the surroundings of Siliguri because of the dense cover of dry foliage and twigs during the ongoing spring led to a cloud of thick smoke that engulfed the city and its outskirts on Tuesday late evening and throughout the night.

Sources in the state forest department have said fire often breaks out because of the foliage and gusty winds during this time of the year and spreads fast in the jungles.

“Fires break out during the spring season because forests unusually become dry. There can also be man-made reasons for such fires. We are keeping a close watch and sent a clear message that nothing should be burnt near the forests these days and any campfire that has been arranged should be extinguished completely,” said Devesh Pandey, the divisional forest officer of the Kurseong forest division.

A tree on fire in the forest near the Bengal Safari Park on Wednesday.

The department asked people living on the fringes of the forests to report to the range and beat offices in case they spot any fire.

On Tuesday, fires broke out in the Baikunthapur forest, which is in the foothills and stretches from northeast to southeast outskirts of Siliguri. Added to it, a stretch of plantation on the Longview tea estate, which is around 25km from here and under the Kurseong subdivision in the Darjeeling district, also caught fire.

Besides, flames leapt out of the forests in the Kurseong forest division.

“These fires led to the smoke that engulfed the city and its surroundings,” said a forester.

Even on Wednesday, flames were seen in some areas of the Baikunthapur forest under its Sarugarah range.

“As the area is close to the Bengal Safari Park, teams from the forest range office reached the spot. They used air blowers to douse the flames. Fire engines from Dabgram were also pressed into service,” said M. Raja, the divisional forest officer of Baikunthapur forest division.

The open-air park, also known as the North Bengal Wild Animals Park, is located on the fringes of the Baikunthapur forest and the Mahananda Wildlife Sanctuary.

The park has 854 animals of 61 species, including the Bengal tiger, lion, Asiatic black bear, hundreds of herbivores and an open aviary.

Raja said the forest department had deployed quick response teams (QRTs) to intervene in case any fire broke out on the outskirts of Siliguri.

“Three QRTs have been posted in the forest range offices. If needed, the teams will rush to the spots concerned to handle the fire. They are also in touch with the state fire services and emergency department and will seek its help if required,” the forester said.

Several Siliguri residents complained of eye irritation and experienced breathing problems because of the thick envelope of smoke.

“The air quality deteriorated in Siliguri because of the smoke. Today (on Wednesday), the air quality index (AQI) of the city was 192, which is higher than the average AQI,” said an environmentalist here.

Usually, the AQI in Siliguri is around 130.

Fires were also reported in some of the forest patches in the Mirik subdivision of Darjeeling district in the past three days. The flames were controlled by the disaster management teams of the subdivision and the fire services department.

“This morning, fires broke out in the Deorali and Bunkulung areas of Mirik block. We have managed to control the fires at these locations,” said Shreyasi Maity, the block development officer of Mirik.