Indoor air pollution: How slum dwellers breathe air more toxic than others

Thirty-two-year-old Besaniya works as a domestic worker in Noida, and lives in a slum called Chaura Basti near the Delhi-Noida border with her two kids. Her husband Ram Deen, who worked as a daily-wage labourer, has been sick with respiratory issues for the past few years. People in her neighbourhood jhuggis also complain of suffocation and breathing difficulties.  

“My husband can’t pick anything heavy and walk for long,” she says. “These winter months become very difficult for him because there is so much pollution,” she adds.  

Just as the winter smog hit Delhi NCR, she sent her sick husband back to their village in Banda district of Uttar Pradesh.  

However, outdoor pollution is not the only issue they face. As the temperature plummets in Delhi NCR and hazardous smog blankets the region, slum and street dwellers relying on wood for cooking and warmth face heightened health risks from pollution. 

 Besaniya and most other people in Chaura Basti use firewood to cook during winter months, as it also helps them keep warm. The slum is built on a small patch of land, left idle in the middle of tall buildings all around. This ensures that the smoke emitted from chulhas gets trapped above the settlement. Every day, after 7pm, as the men in the family come back from work, women light the chulhas for cooking and warming.   

“This helps us get rid of the expensive LPG and also keeps us warm in this biting cold,” said Raj Narayan, a resident of the Basti. By 8pm, the entire slum gets engulfed in smoke, visibility decreases, and tears well up in the eyes. The women who cook blow air into the stove through a pipe, coughing continuously as they do so. 

Deepali and her mother-in-law cook for the family in Chaura Basti, Noida | Sneha Richhariya/First Check

“We inhale dust and fumes all day; we also fall sick two to three times a month during these winter months,”  said Deepali, Raj Narayan’s daughter-in-law, who also lights a chulha every day. Deepali also has a four-year-old daughter, who sits with her mother as she cooks on the mud stove and struggles with the fumes.  

Indoor air pollution arises from various sources, including smoke from fuels used for cooking and heating, tobacco smoke, building materials like paints, varnishes, and wood flooring, adhesives in furniture and electronics, broken CFLs and tube lights, high moisture levels, and overall outdoor air pollution. 

Among these sources, the burning of solid fuels for cooking is the primary contributor to indoor air pollution in India. In most Indian households, PM2.5 concentrations range between 86 and 882 µg/m3. Higher PM2.5 levels in enclosed spaces are ten times more dangerous than similar concentrations outdoors, as confined environments allow pollutants to accumulate more than open areas. 

The dangers of indoor air pollution

Outdoor air pollution in Delhi is primarily caused by vehicle emissions, power plants, small industries like brick kilns, dust from traffic and construction, open waste burning, and diesel generators. Household air pollution is primarily caused by burning coal, which is particularly dangerous due to its close proximity.  

In poorly ventilated homes, indoor smoke can have fine particle levels up to 100 times higher than what is considered safe. Inefficient cooking fuels like wood and kerosene release tiny soot particles that can deeply penetrate the lungs, worsening the health risks. 

Dr Nikhil Modi, Senior Consultant, Department Of Respiratory, Critical Care and Sleep Medicine, Apollo Hospital in New Delhi, highlighted that indoor air pollution, particularly from burning wood and coal for cooking or heating, can be significantly more harmful than outdoor pollution, often being 4 to 5 times more dangerous.  

“Indoor pollution involves fine soot particles and gases like carbon monoxide and carbon dioxide, which can cause severe health issues,” he emphasised. 

A 2015 study published in the Lancet journal found that air pollution was responsible for 5.2 lakh premature deaths in India. The leading cause of these deaths was household air pollution, primarily from solid cooking fuels, which contributed to 1.2 lakh premature fatalities.  

Household air pollution accounts for 44% of all pneumonia deaths worldwide in children under five, with nearly half of all lower respiratory infection deaths in this age group attributed to soot inhalation. The WHO also notes links between household air pollution and risks of low birth weight, tuberculosis, cataracts, and cancers of the nasopharynx and larynx. 

Pregnant women, children: the silent victims of indoor air pollution?

Dr Yasmeena, who works as a medical officer in-charge at a Rural Health Training Centre, affiliated with Jamia Hamdard University, witnesses the impacts of dirty fuels almost on a daily basis.  

“I deal with respiratory issues in pregnant women on a daily basis, especially during winter months; they are particularly affected by pollution, primarily due to their lowered immunity during pregnancy… This makes them more susceptible to respiratory issues and other health complications during high-pollution periods,” she said. 

Chaura Basti is crowded with small children playing and running all around | Sneha Ricchariya/First Check

A 2012 study revealed that women using biomass, kerosene, and coal for cooking faced a significantly higher risk of having low birth weight babies compared to those using the much cleaner liquefied petroleum gas. Similarly, a 2013 study found that the use of firewood, biomass (such as crop residue, dried vegetation, or even waste), and kerosene was linked to an increased chance of stillbirths.

But despite the risks, not all women can avoid the harmful fumes. Gudiya, a resident of Chaura Basti, gave birth to three children in the locality, the youngest of whom was just a year ago. “The doctors told me to avoid firewood, but if I don’t use it, who will cook for the family?” she asked.  

Not just pregnant women but also children bear the brunt of indoor pollution. A 2018 study explored the link between indoor air pollution and asthma in children in Delhi. It examined 3,104 children across industrial, residential, and village areas. The findings reveal that 7.9% of children had asthma, with the highest prevalence in industrial areas (11.8%). The study finds that biomass fuel use, tobacco smoke, and elevated indoor suspended particulate matter (SPM), particularly in industrial zones, were the key contributors. The health effects were more severe in people from lower class areas than in upper and middle class, as per the study. 

Chaura Basti is crowded with small children playing and running all around. As mothers cook and fathers wait for food, children sit near the mud stoves with their mothers to warm themselves.  

Confined spaces make indoor pollution worse

Delhi’s air quality during the winter months often falls into the “severe” or “dangerous” categories, with AQI levels soaring well beyond acceptable limits. In slums like Chaura Basti, the situation is exacerbated by indoor pollution, where fumes can contain particulate matter up to 100 times finer than outdoor pollutants.  

On the day this story was reported, a monitoring station in Vasundhara Enclave, located near Chaura Basti, recorded an AQI of 486, placing it in the hazardous category. However, the reality of areas such as Chaura Basti, where harmful fumes are trapped because of the way the area is planned, could be worse. 

“AQI is typically monitored at specific locations that are often open, well-maintained, and surrounded by trees or good infrastructure. This leaves us unaware of how much worse the air quality might be in poorly ventilated areas,” Dr. Dileep Mavalankar, former director of the Indian Institute of Public Health, Gandhinagar, explained.  

Apart from the neighbouring government hospital, the residents visit a 'Bengali Dawakhana' located next to the slum | Sneha Richhariya/First Check

A study conducted in 92 households, involving 174 women, provides evidence of the harmful effects of indoor air pollution from biomass combustion on health. The results revealed significantly higher levels of particulate matter (PM2.5) in households where a separate cooking room was not used for biomass fuel. 

To address the issue of biomass burning, Prime Minister Narendra Modi launched the Pradhan Mantri Ujjwala Yojna in May 2016. The scheme aimed to provide free LPG connections to families living below the poverty line.

In the first year, the scheme covered 2.2 crore households, exceeding its target of 1.5 crore connections. The scheme was then rolled out to 5 crore more families. However, beneficiaries started dropping out after exhausting the free gas cylinder, as refilling remains a major issue to date. 

Due to difficulty in obtaining LPG refills, increasing costs and lack of proper documentation among migrant families, women have been forced to rely on firewood stoves and heating devices. During winter months, almost all residents of Chaura Basti move to mud stoves. 

The residents of Chaura Basti remain largely unaware of the harmful effects of the fumes they breathe in daily. Many chalk up their symptoms to temporary, seasonal ailments. 

Apart from the neighbouring government hospital, the residents visit a “Bengali Dawakhana” located next to the slum.

“My main job is this,” Dr N.K. Mollick said, pointing to the board at the gate of his clinic, which says he specialises in treating diseases like piles and fistula. “Sometimes, patients come with breathing issues, so I also nebulise them,” he added.  

"Aap log toh apne ghar mein heater laga sakte hain, hum kya kare itni thand mein? Isliye chulha jalate hain [You can afford to use heaters in your homes, but what can we do in this cold? That's why we keep the stove burning]," explained Raj Narayan, waiting patiently for his meal. Just a few meters away, his wife and daughter-in-law prepare chapatis on a mud stove while children play nearby.  

It’s now 8.30pm, and as the stoves are lit, the air in the narrow lane becomes thick, making it difficult to breathe, with a haze settling over everything.

This story is done in collaboration with First Check, which is the health journalism vertical of DataLEADS.