What is the issue?
- Haze loomed over Delhi and its adjoining areas for over a week.
- The causes and consequences of it demand a more holistic approach in responding to this environmental problem.
How is the dust pollution scenario in Delhi?
- Air quality - For over five days, a thick layer of dust hung over Delhi.
- It kept the air quality ‘severe’, the worst category in the pollution index.
- It was odd because it happened in the peak summer.
- Summer is generally considered the off-season for air pollution in Delhi.
- Pollutant - The major air pollution threat in Delhi is from the tiny PM2.5 particles.
- However, during the summer, PM10 is found to be the primary pollutant.
- The summer average for PM10 in Delhi was found to be 5 times the national average.
- About 40% of PM10 particles (with diameter less than 10 micron) was dust.
- Dust - Windblown dust consists of soil, sand and rock particles.
- Besides, it also contains “re-suspended” dust kicked up by vehicles, digging or construction.
- The dust hosts toxic materials, including, heavy metals such as lead, chromium and nickel.
What are the causes?
- The recent phenomenon was triggered by a dust storm that began over Rajasthan.
- It was carried by strong westerly wind.
- The dusty blanket spread itself over Punjab, Haryana, Delhi and western UP.
- It was kept close to the surface by the anticyclonic flow of winds.
- Anti-cyclones swirl clockwise in the northern hemisphere.
- It pushes the local air down and prevents outside air from entering the region.
What are the changing conditions?
- The recent dust haze is notably not a one time incident resulting just from desert storm.
- The phenomenon could be aggravated by
- desertification around Delhi
- the uncontrolled urban development
- climate change
- Delhi’s summer aandhis, like Kolkata’s kaalbaisakhis, are localised events.
- However, the recent development is different in scale and impact.
- Strangely, all of North India was enveloped.
- These climatic conditions cannot any longer be seen in isolation.
Why is desertification a serious issue?
- What - Desertification is the process of relatively dry land becoming increasingly arid.
- It refers to a condition of reduction of water supplies and lowering of water table in the soil.
- The factors range from loss of vegetation and overexploitation of soil to climate change.
- Scale - The rate of desertification in India is said to be at 23 hectares of dryland per minute.
- Nearly 70% of India’s area is dryland.
- A third of this is affected by degradation and a quarter by desertification.
- Rajasthan and Delhi were among the worst affected.
- Impact - Delhi has historically had a barrier of trees.
- This exists in the form of the Delhi Ridge and the linked Aravalli range.
- But nearly 12 vegetative gaps in southern Haryana are increasingly prone to desertification.
- The forest cover in Haryana, UP and Rajasthan is also found to be declining.
- Significance - Preventing desertification is crucial because failing on this would result in more dust.
How to address this?
- Preparing for more climate related incidents in the future should be a priority.
- Australia and several countries in sub-Saharan Africa and West Asia carry out dustfall monitoring.
- Measuring dust deposits in the air alongside ambient air monitoring can be done.
- The data would help in the mitigation processes.
- Projects like the African Union-led “Great Green Wall for the Sahara and Sahel Initiative” could be taken up.
- It aims to create a mosaic of trees across North Africa, Sahel and the Horn.
- Vegetation buffers could be positioned between residential and industrial areas or roads.
- The urban design of Delhi should be rethought.
- Greening has to be done intelligently; roads need to be designed with tree cover.
- The Aravalli and the Ridge need to be protected.
- This in turn will protect the water table and benefit the city throughout the year.
Source: Indian Express
