Delhi NCR’s air quality hits a dangerous level: How to choose the right air purifier in 2025

As winter approaches, Delhi NCR’s air quality is heading into the danger zone. On Wednesday, the city recorded an Air Quality Index (AQI) of 207, classified as “Severe,” with PM2.5 levels at unhealthy highs. Breathing this air can affect everyone, but children, the elderly, and people with respiratory conditions are at greater risk. For many residents, investing in an air purifier has become essential.

Here’s what you need to look out for while buying an air purifier in 2025

Size, coverage, and Clean Air Delivery Rate (CADR)

Not all air purifiers are built the same. One of the first things to check is the size of the room you want to use it in. A purifier too small for a large living room will struggle to clean the air effectively. Look for the Clean Air Delivery Rate, or CADR, which indicates how quickly a purifier can remove particles like dust, smoke, and pollen. Higher CADR numbers generally mean faster and more efficient cleaning.

Filters and maintenance

Delhi’s winter air carries a mix of dust, PM2.5, smoke, and odours. If you are planning to buy an air purifier, prioritise the ones with high CADR, efficient HEPA filters, and activated carbon layers to trap pollutants effectively. This ensures cleaner air indoors even when the outdoor AQI is in the “Severe” range.

Keep in mind that filters need regular replacement. A purifier with a clogged filter will not work properly, and replacing them on time keeps the machine effective. Check the cost and availability of replacement filters before making a purchase.

Noise levels for bedroom use

In Delhi winters, pollution often spikes early in the morning and late at night, when people are indoors. If you plan to keep an air purifier in your bedroom, look for models with quiet or sleep modes. These run silently without disturbing your sleep while cleaning harmful PM2.5 particles that peak at night.

Energy consumption during long-use periods

During Delhi’s smoggy months, purifiers may need to run almost all day. Energy-efficient models help avoid high electricity bills. Some purifiers also adjust fan speed automatically based on indoor air quality, which is useful when outdoor pollution fluctuates due to traffic or stubble burning in nearby states.

Smart features for real-time pollution monitoring

Devices with built-in sensors can show real-time indoor AQI and adjust airflow automatically. In Delhi, where air quality can deteriorate suddenly, this ensures your purifier responds immediately without constant manual intervention. Some models even allow remote monitoring via apps, so you can start purifying your home before you return from the office.

Portability for multi-room coverage

Many homes have multiple living spaces where family members spend time. Smaller, portable purifiers can be moved between bedrooms, living rooms, and study areas, while larger units are better suited for bigger rooms like lounges where families gather during winter evenings.

Health impact during peak pollution months

With AQI frequently hitting severe levels, a good air purifier is no longer a luxury; it’s essential for protecting respiratory health. Choosing the right purifier can significantly reduce exposure to harmful particles, especially for children, the elderly, and people with asthma or other lung conditions.