Key facts
- Delhi's average carbon monoxide concentration from January to May was 1.89 mg/NM3.
- This average is the highest recorded level since 2022.
- January's average CO concentration of 2.5 mg/NM3 was the highest for the month in five years.
- February's average CO concentration of 2.20 mg/NM3 was the highest since February 2021.
- March's average CO concentration of 1.90 mg/NM3 was the highest since March 2017.
- Carbon monoxide is a toxic gas that reduces the blood's oxygen-carrying capacity.
Delhi has experienced a gradual increase in carbon monoxide (CO) levels from January to May this year, with monthly averages reaching their highest points in several years. Data from Envirocatalysts shows the January-May average CO concentration at 1.89 mg/NM3, the highest since 2022. January recorded the highest monthly average in five years at 2.5 mg/NM3, while February and March also saw elevated levels compared to previous years.
Carbon monoxide is a toxic gas that impairs the blood's ability to transport oxygen, potentially leading to headaches, dizziness, fatigue, and cardiovascular complications with prolonged exposure. Indian standards set the permissible limit at 2 mg/NM3 for an 8-hour average, with WHO guidelines at 4 mg/NM3 for a 24-hour average. While many days remained within or below the Indian standard, some days saw levels reach 3 mg/NM3.
Experts attribute the rise in CO levels to high vehicle numbers and local combustion activities. Sunil Dahiya of Envirocatalysts suggests curtailing combustion, particularly increasing private vehicle ownership, and shifting towards electric public transportation to reduce pollution and improve city livability. Physicians highlight the severe health risks, especially for pregnant women, children, and the elderly, due to oxygen depletion in the bloodstream.