Air pollution in the national capital is not only threatening human health but is also taking a serious toll on urban greenery, according to a recent study conducted by Delhi University. The research reveals that prolonged exposure to high levels of air pollutants has significantly harmed trees across Delhi, affecting their growth, physiological functions, and overall vitality.
The study highlights that trees in the city are increasingly struggling to survive under sustained pollution stress. Researchers observed that long-term exposure to toxic air has negatively impacted key biological processes, including photosynthesis, which is essential for plant growth and survival. As a result, many trees are showing visible signs of stress and declining health.
According to the findings, elevated concentrations of particulate matter and other harmful air pollutants are causing direct damage to leaf surfaces. The pollutants accumulate on leaves, interfering with their ability to absorb sunlight and carry out photosynthesis efficiently. Scientists noted a reduction in chlorophyll content — the pigment responsible for photosynthesis — which weakens the trees’ capacity to produce energy and grow normally.
The research also found that pollution exposure compromises the natural defence mechanisms of trees. With their protective systems weakened, trees become more susceptible to diseases, pest infestations, and environmental stressors such as heat and drought. This increased vulnerability further accelerates their decline, especially in heavily polluted areas of the city.
Researchers warned that deteriorating tree health could trigger a harmful feedback loop. Trees play a crucial role in filtering air pollutants and improving urban air quality. However, as pollution weakens them, their ability to absorb harmful particles and gases diminishes. This reduced filtering capacity can lead to even higher pollution levels, placing additional stress on already vulnerable vegetation.
The study emphasised that this cycle poses a serious ecological concern for Delhi. Urban trees are a critical component of the city’s environmental defence system, helping regulate temperature, support biodiversity, and mitigate air pollution. A decline in their health could undermine these functions, worsening both environmental and public health challenges.
Scientists involved in the study stressed that protecting and strengthening urban greenery must be a priority in efforts to combat air pollution. They pointed out that trees act as natural air purifiers and are essential for maintaining ecological balance in densely populated cities like Delhi. Without healthy trees, the city’s ability to cope with pollution will be significantly reduced.
The researchers called for stricter pollution control measures to reduce the burden of toxic pollutants on both people and the environment. They also highlighted the need for better urban planning that takes into account the protection and expansion of green spaces. Ensuring that trees are planted in suitable locations and maintained properly, they said, would help improve their resilience to pollution stress.
In addition, the study underlined the importance of recognising trees as living organisms that require protection, rather than merely decorative elements of urban landscapes. Regular monitoring of tree health, pollution-resistant planting strategies, and sustained efforts to reduce emissions were identified as key steps to safeguard Delhi’s urban forests.
The findings add a new dimension to the ongoing debate around air pollution in the capital, underscoring that the crisis extends beyond human health impacts. As pollution levels remain persistently high, the study warns that neglecting the health of trees could have long-term consequences for the city’s environment and livability.
