AQI above 400 is 'severe' and can affect healthy people and seriously impact those with illnesses.
Hospitals in Delhi are teeming with people suffering from cough, nasal congestion, shortness of breath and even asthma attacks as an eye-stinging smog blankets the national capital.
With Delhi's air quality remaining 'severe', doctors advised a return to wearing masks to guard against pollution.
While forecasters on Wednesday predicted the air quality to improve due to stronger winds, Delhi's overall Air Quality Index (AQI) stood at 426 at 9:10 am.
An AQI of above 400 is considered 'severe' and can affect healthy people and seriously impact those with existing illnesses.
At Holy Family Hospital in Okhla, there has been a 30 per cent increase in such patients coming to out-patient departments, said Dr Sumit Ray, head of department of critical care.
Last year, the hospital had started writing "pollution-related" in diagnosis in what was probably a first for a medical facility here.
"There were two ICU (intensive care unit) patients for whom we wrote that diagnosis. For writing that diagnosis, you have to rule out several probable factors that could have triggered the illness. For the patients who are currently admitted, we will need a few more days to arrive at that diagnosis," Dr Ray said.
Shedding light on the problems faced by patients, Dr Ashish Kumar Prakash, consultant (respiratory and sleep medicine) at Medanta in Gurugram, said they had been attending to patients complaining of cough, nasal congestion and breathing difficulty since Diwali.
"Currently, I have 25 to 30 patients in my OPD with such conditions and the entire unit/department has approximately 50-75 cases in total. Patients suffering from respiratory illnesses such as COPD, asthma, and others are reporting acute exacerbations, an increase in symptoms such as coughing, dyspnea and acute nasal problems," he said.
Dr Prakash said apart from worsening AQI, the change in weather was another factor behind a lot of the problems in patients with respiratory illnesses.
"As the weather transitions to cold and breezy, the cold, dry air and sudden shifts in the weather can irritate the airways, causing one to produce more mucus and leading to exacerbations if the patients are not taking their medications properly," he said.
Dr Suresh Singh Naruka, senior consultant (ENT) at Indraprastha Apollo Hospitals in Delhi, said there has a been a "significant jump" in the number of patients visiting him in his OPD post Diwali due to rising pollution levels.
"ENT patients have been showing hyper response since Diwali and they are coming with increased coughing, runny nose, nasal symptoms, watery eyes. Among the patients I am seeing daily, 50 per cent of those are related to allergic symptoms induced by pollution, which earlier was about 10-15 per cent," Naruka told PTI. Hospitals are also seeing patients with no previous history of respiratory ailments coming for treatment.
When the respiratory system is affected, it can lead to persistent cough, said Dr Ravi Shekhar Jha, director (pulmonology) at Fortis Escorts Hospital in Faridabad.
Nowadays, even patients with no previous history of respiratory illnesses are coming with severe intractable cough and breathing difficulty.
"Those patients who have respiratory history like asthma are getting more frequent attacks and even inside the hospital, patients are taking more than usual to recover from asthma and COPD attacks. Viral infection is fairly common in this weather but even those who did not have any evidence of viral infection are taking longer and higher doses of medicines for recovery," he told PTI.
Dr Hemant Kalra, a chest specialist at Maharaja Agrasen Hospital in New Delhi, concurred with Jha and said the rise in pollution along with the cold and dry air due to the changing season could irritate the airways and cause symptoms such as shortness of breath, coughing, wheezing and asthma attacks.
Excessive, continuous exposure to polluted air not only worsens pre-existing respiratory conditions leading to frequent asthma attacks and COPD flare-ups but also newer cases, he asserted.
He advised patients to follow preventive measures like staying indoors or wearing a face mask when stepping out.
"This should be combined with a ready action plan prepared in consultation with your doctor, an inhaler by your side in the case of asthmatics and taking regular inhalation therapy as prescribed by your doctor. Additionally, a peak flow meter can also be used to monitor your lung health and manage your condition better," he said.
Jha said people have stopped wearing masks and advised people to start using them again.
"People in the habit of wearing masks are getting fewer attacks. It is also very important to note that normal masks do not protect us properly from particulate matter (PM2.5), so wearing an N95 mask with a valve/filter is recommended," he said.
Many doctors are also recommending patients to use air filters at home and avoid stepping out during early morning and evening, especially the vulnerable like the elderly, children and people with respiratory ailments.
Dr Rahul Sharma, additional director (pulmonology) at Fortis Hospital in Noida, said, "HEPA (high efficiency particulate) filters work well and we recommend them to patients, especially those who are homebound.
"The purifier works in a limited cubic metre of space. While buying a purifier one should check the capacity of how much air it can purify in accordance with the capacity of your home. Another important thing is that there are HEPA filters and HEPA-like filters, which are not as effective as HEPA filters."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)