Ayena was trying to be as quick as possible, adding woodchips to the flame under a clay cooking stove by a roadside in the capital's Rampura. A crowd of half a dozen people was waiting for her to deliver the pithas (a kind of cake).

Every winter, she sets a little pitha shop out in the open, selling the sweet and savory treats every day to make a living. What Ayena doesn't realise is that the smoke from the traditional clay stoves can actually kill her.

Like 34-year-old Ayena, many middle-aged women sell pithas on the roadside during winter. They use firewood and clay stoves to make them, completely unaware that this can lead to hazardous impacts on health. They remain oblivious that the smoke spewing from traditional clay stoves can cause cancer.

According to a study by the Medical Oncology Department, National Institute of Cancer Research and Hospital (NICRH), lung cancer is the most common cancer in women. It shows that 12 percent of about 1,500 women diagnosed with cancer are patients of lung cancer.

An increasing number of women are being diagnosed with lung cancer after years of exposure to black smoke, said Dr Muhammad Rafiqul, lead researcher of the study. He further added that the average age of female lung cancer patient is 55.25 years old.

“Passive smoking can cause lung cancer too,” he added.

The study was done on cancer patients who visited the NICRH's Oncology Department between January and June 2018. 

Explaining why the findings have raised concerns, Rafiqul said that most women in Bangladesh don't smoke, but lung cancer is as prevalent here as it is in the USA where smoking is commonplace among women.

One reason for this high prevalence of lung cancer in women in the country could be the practice of cooking with firewood, he added.

“Cooking with firewood is an age-old tradition in the country. However, women were never detected with lung cancer before as they wouldn't visit doctors even after suffering symptoms.”

According to the World Health Organization, around 1.17 lakh people die in Bangladesh every year due to exposure to smoke and harmful chemicals from clay stoves.

Talking to The Daily Star, Ayena said smoke emitting from the stove irritated her eyes and throat.

In low-income households, both in urban and rural settings, women are exposed to indoor pollution because of these traditional stoves.

48-year-old Jamila Khatun, who regularly used a traditional clay stove, from Kishoregonj is suffering from lung cancer.

Jamila has recently been admitted to NICRH. She has been suffering with lung cancer for two years and has taken eight chemotherapies.

If cancer is diagnosed at the first stage, it is treatable, said Rafiqul.

Targeted therapy that uses drugs to block the growth and spread of cancer cells all over the body is an alternative to chemotherapy and gives better results.

But women come to NICRH when cancer reaches the third stage. Before that they try out so-called herbal treatment or “kabiraj”.

The head of the Pulmonology department of Dhaka Medical College Hospital (DMCH), Biswas Akhtar Hossen, informed that chronic obstructive pulmonary diseases are associated with biomass gas, which can also lead to serious lung problems.

Biomass gas is emitted from burning firewood, and women get exposed to that while cooking on clay stoves, he said. Pulmonology is a medical specialty that deals with diseases affecting respiratory tract.

The government developed an action plan in 2013 with a goal to reach three crore households with clean cooking solutions. The goal is set for 2030.

More than 1.65 million improved cooking stoves were distributed among the rural households till January 2019 by the state-owned financial institution, Infrastructure Development Company Ltd (Idcol). The German International Cooperation Agency, GIZ along with partners installed 2.6 million environment friendly stoves, known as Bandhu Chula throughout Bangladesh since 2006.