Context: A study published in the journal Climate and Atmospheric Science highlighted that stubble burning only contributes about 14% of PM 2.5 in Delhi-NCR and is therefore not a primary source of particulate matter concentration in Delhi-NCR.
Relevance of the Topic: Prelims: Questions based on pollutants like PM 2.5 and PM 10.
Key Findings of the Study
- The report claims there is no linear correlation between stubble-burning events in Punjab and Haryana and fine particulate matter (PM2.5) concentration in Delhi-NCR.
- It highlighted that PM 2.5 concentration remained stable, despite stubble burning in the Punjab and Haryana declining by over 50% from 2015 to 2023.
- Contradictory trends: There is a contrast in the stubble burning and concentration of PM2.5 in Delhi-NCR:
| Trend of stubble burning | PM2.5 concentration |
|---|---|
| Stubble burning in Punjab and Haryana declined by 31% and 37% respectively in 2023 compared to 2022. | 20% increase in PM2.5 (as per sensor at the U.S. Embassy in 2023). |
| Stubble burning ceased after November. | The Air Quality Index in Delhi-NCR in December to February has remained in the ‘very poor’ to ‘severe’ category since 2016. |
- Day and Night variation: The day and night variation of PM2.5 and Carbon Monoxide (CO) points towards other sources of pollution other than stubble burning.
- Night concentration of PM 2.5 is 20% more as compared to day throughout the year. Whereas, such clear variation is witnessed in Punjab-Haryana during stubble burning months only. This reflects the contribution of other sources in pollution.
- As such clear variation is observed in Punjab and Haryana during stubble burning months, but in Delhi-NCR such variation is constant throughout the year.
- Visible reflection of interventions: The reduction in the pollution and improvement in air quality after implementation of Graded Response Action Plan (GRAP) reduced PM 2.5 levels significantly. These stringent transport control and regulation of construction activities underscored the possibility of other major sources of pollutants.
- Supported by other studies- Another study of IIT Kanpur also supported the claim that stubble burning contributes about 13% PM2.5 and that too only during October and November.
Other reasons for PM 2.5 apart from stubble burning
- Alternate pollution sources: Another study of IIT Kanpur has identified that the transport sector is the largest contributor of the PM 2.5 i.e., 30%, followed by local biomass burning (23%), construction industry (10%) and industry (5-7%). These pollutant sources contributed to PM 2.5 in continuous manner.
- Stagnant winds: The Delhi-NCR region has stagnant winds, lower mixing heights and inversion conditions from the month of December to February intensifies the pollution in the region.
- Land-locked conditions of Delhi-NCR and delayed mobilisation of pollutants leads to the constant degradation of the air quality in the region.
- Dip in temperature: Temperature in North India faces a dip from months of November to January. Further, dry conditions during winters intensifies the severity of the pollution.
- Unsustainable practices: Sectors like constructions follow unsustainable practices by violating the construction by-laws. This further aggravates the condition of pollution in India.
- Laxed enforcement of laws: Vehicle control and pollution control rules lack proper implementation. Old diesel vehicles and poor monitoring of pollution norms leads to the intensification of PM 2.5 and CO concentration, impacting air quality negatively.
About PM 2.5
- Fine particulate matter (≤2.5 micrometers) suspended in air.
- Sources: Vehicle emissions, biomass burning, construction dust, and industrial pollution.
- Remains airborne for long periods and travels deep into the respiratory system.
- Direct impacts of persistent exposure to PM2.5:
- Respiratory Issues: Triggers asthma, bronchitis, lung infections, and reduces lung function.
- Cardiovascular Diseases: Increases risk of heart attacks, strokes, high blood pressure, and arrhythmia.
- Neurological Effects: Linked to cognitive decline, memory loss, and increased risk of dementia.
- Impact on Children & Pregnant Women: Causes low birth weight, preterm births, and hampers lung development in children.
- Eye & Skin Irritation: Leads to eye redness, itching, and skin allergies.
- Reduced Life Expectancy: Long-term exposure can cause chronic illnesses, lung cancer, and premature death.
Instead of scapegoating stubble burning, there should be constant enforcement of pollution control laws, promotion of public vehicles and installation of mitigative equipment like Smog towers to reduce the menace of pollution in Delhi-NCR.
