Biodiversity parks: A solution to stubble burning in Delhi NCR

Stubble burning in northern India poses a severe environmental challenge, degrading air quality and intensifying pollution in Delhi and nearby areas. Due to limited time before wheat sowing, farmers often resort to burning crop residues, despite its harmful impact on the environment.

Innovative solutions, including repurposing stubble for biodiesel, paper, and cattle feed, alongside developing biodiversity parks to curb PM2.5 levels, are under consideration. A balanced approach is essential to address both farmers’ economic needs and environmental sustainability effectively.

Stubble burning has become a critical environmental issue in recent years, severely impacting air quality in Delhi and neighboring regions. The rise in AQI levels has made the air toxic, causing severe discomfort and breathing difficulties for residents. This problem is exacerbated by the growing demand for rice, leading farmers in northern India to expand rice cultivation, even in areas traditionally reserved for monsoon crops. Rice is transplanted in June or July and harvested by early October. However, extensive cultivation leaves behind straw, which is not harvested along with the grains. With wheat sowing beginning in early November, there is insufficient time for natural decomposition, forcing many farmers to burn the stubble. While this is the most practical solution for handling crop residues, it contributes to smog and toxic air, particularly in October and November when low wind velocity traps pollutants in the lower atmosphere, worsening air quality.

Efforts to prevent stubble burning have focused on repurposing crop residues. The residues can be used for cattle feed, mushroom cultivation, or even paper production. However, converting rice straw into paper faces challenges due to lignin, a tough substance that is difficult to break down. The process of dissolving lignin with acid creates harmful effluents that contaminate the soil, making it environmentally unsustainable. Another potential solution being explored is converting rice straw into biodiesel, with ongoing research in Punjab. However, the technology is still in its early stages. The Punjab government is also considering alternatives to rice cultivation, such as growing crops that don’t produce stubble, but this could reduce farmers’ income. While some NGOs have had success in convincing farmers to switch to pulses, widespread adoption remains a challenge.

The increasing severity of stubble burning is also linked to changes in the atmosphere’s ability to absorb pollutants. The resilience of the atmosphere in the National Capital Region (NCR) has decreased, reducing its capacity to manage emissions from stubble burning. This is compounded by the presence of millions of vehicles, which add to the pollution. Additionally, weather conditions, such as low wind velocity in October and November, prevent pollutants from dispersing, allowing them to accumulate in the lower atmosphere and reach toxic levels. While stubble burning is a major contributor to poor air quality, it is not the sole factor. PM2.5, a particulate matter composed of dust and bio-dust, also plays a significant role. In Delhi, trees, which are often covered with a layer of dust, act as filters, preventing the dust from being suspended in the air. Without these trees, pollution would worsen.

To address the AQI issue, experts propose the creation of biodiversity parks and vegetation buffers. These green spaces, consisting of multi-layered vegetation, can absorb dust and pollutants, preventing them from entering the air. Studies by the National Environmental Engineering Research Institute (NEERI) at the Aravali Biodiversity Park showed a 50% reduction in PM2.5 levels after the air passed through the park. Developing such parks across Delhi and the NCR could play a crucial role in improving air quality. In addition, the economic challenges faced by farmers must be considered. Many cannot afford expensive machinery for harvesting rice, making stubble burning a more accessible option. As a result, solutions must be developed that support farmers while addressing the environmental impact.

International collaborations, such as those between the Punjab Agricultural University and Japanese research institutions, are exploring ways to decompose lignin and convert stubble into useful products, such as biodiesel and paperboards. The Indian Agricultural Research Institute has also developed a material that may help decompose crop residues, but further research is needed to assess its effectiveness. Ultimately, a holistic approach is required to address the issue of stubble burning, balancing environmental protection with farmers’ economic needs. Developing vegetation buffers and biodiversity parks, especially in institutional areas and public spaces, could significantly reduce PM2.5 levels, improving air quality and benefiting the ecosystem.

Stubble burning is a complex issue that requires a multifaceted solution. While technological advancements in biomass recycling are essential, creating green infrastructure such as biodiversity parks offers a promising way to reduce pollution and protect public health in Delhi and the surrounding NCR region.

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For this column, IBT interacted with Dr. C. R. Babu. A distinguished conservationist and the founding director of Delhi University’s Centre for Environmental Management of Degraded Ecosystems, Dr. Babu is renowned for his pioneering work in ecological sustainability.

Often called the “Green Doctor” for his instrumental role in establishing Delhi’s biodiversity parks, Dr. Babu has spent decades fostering environmental harmony. As a former pro vice chancellor of Delhi University, he continues to shape the future of conservation, sharing his expertise on pressing environmental challenges, including the cleaning of the Yamuna River.