The demand for air purifiers and masks has shot up in Delhi-NCR amid increasing levels of pollution in the region, merchants and pharmacists said.

The air quality index in the national capital on Friday breached the 450 mark, raising an alarm for emergency measures to be enforced under the Centre's third stage of Graded Response Action Plan, GRAP-III.

"We have seen a 20-25 per cent increase in the demand for air purifiers in the last couple days. Due to the deteriorating condition of air quality in the city, more and more people are now looking to purchase air purifiers," a shopkeeper based in Delhi's Rajouri Garden said.

When compared to the last year, the surge in the demand for air purifiers this year has just started to grow up, another shopkeeper in Ghaziabad said, while adding that the sale of air purifiers is expected to further swell up in the coming days.

"This is just the beginning of the surge. If the air quality continues to get worse, the demand for air purifiers is expected to grow more," a Dwarka-based shopkeeper said.

Amid the shooting air pollution in Delhi majorly caused by the farm fires in northern part of Haryana and Punjab ahead of Diwali, demand for masks have also increased, pharmacists in Delhi said.

Customers are mostly looking to buy N95 masks to get extra protection from the harmful particles in the air, they added.

The air quality condition in Delhi turned worrisome as dense and pungent haze engulfed the city and its surrounding areas for the fourth consecutive day on Friday.

The weather office has warned that the level of PM2.5, fine particulate matter capable of penetrating deep into the respiratory system and triggering health problems, has exceeded the safe limit of 60 micrograms per cubic metre by seven to eight times at multiple locations across the region.

Medical experts at both government and private hospitals have cautioned people not to venture out early morning for exercise or taking a walk and asked them to wear a mask when stepping out for work or market or other places.

"We are seeing cases now as well of prolonged coughing, throat infection, eye irritation and nasal discharge, and other kinds of irritation," Suranjit Chatterjee, senior consultant, internal medicine at Apollo Hospital, Delhi, told PTI. The doctor suggested using "good-quality purifiers at home" and said that measures to curb pollution in the city requires efforts at both government as well as individual level.

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