Dr Shuja Ahmed Mahesar
HOW can we protect our environment from the water and air pollution caused by artificial fertilizers and pesticides used for agricultural productivity and by fossil fuels consumed by industry? This question lies at the heart of today’s environmental crisis caused by the dwindling of freshwater resources at precarious rate. Water is vital to human survival, forming a major part of all living organisms. Beyond domestic use, it is indispensable for industry as a solvent, coolant and chemical reactant. Despite being neutral and colorless, water quality worldwide is increasingly compromised by biological and chemical pollutants. The growing shortage of clean freshwater has contributed to waterborne diseases such as cholera, typhoid and diarrhoea. Its ability to dissolve a wide range of substances makes it particularly vulnerable to contamination. Nitrates and phosphates from agricultural waste, along with excessive use of fertilizers like ammonium phosphate, significantly pollute water and soil.
Carbon dioxide and Sulphur dioxide emitted by vehicles and industries cause the acidification of rainwater, a process further intensified by nitrogen dioxide. Moreover, toxic industrial effluents containing heavy metals such as cadmium and mercury contaminate rivers and groundwater. Insoluble waste, particularly plastic, has emerged as a major source of pollution in rivers, lakes and reservoirs. Persistent, non-biodegradable chemical substances further exacerbate water pollution due to their stability and resistance to natural breakdown. Air pollution is closely linked to rising concentrations of greenhouse gases in the atmosphere. Elevated levels of carbon dioxide trap the Sun’s heat and lead to global warming, the primary driver of climate change. While the Earth naturally absorbs and radiates energy to maintain a stable temperature, greenhouse gases such as carbon dioxide and methane—produced by industry and agriculture—disrupt this balance by preventing heat from escaping into space. Deforestation significantly accelerates global warming by increasing carbon dioxide levels. Nevertheless, trees act as the lungs of the Earth, absorbing carbon dioxide and releasing oxygen.
To reduce carbon emissions, collective global action is essential. All nations must commit to implementing international agreements such as the Kyoto Protocol and the Paris Accord to curb the burning of fossil fuels. Large-scale tree plantation and restoring mangrove forests is a natural and effective way to absorb carbon dioxide and mitigate climate change. Since fossil fuels are neither renewable nor sustainable, reducing their consumption is imperative. Greater reliance on alternative, sustainable energy sources is the need of the hour. In addition, sustainable agricultural practices can help lower methane emissions released into the atmosphere.
Environmental degradation is driven by emissions from conventional energy sources. Pollution can be reduced by transitioning to renewable energy such as hydropower, solar and wind. While the initial cost of renewable infrastructure is high, the long-term environmental benefits are substantial. Some countries are phasing out nuclear power due to safety and waste concerns. Coal-and gas-generated electricity has significant environmental consequences, whereas wind energy can be cost-competitive without harm. Although solar and wind are intermittent, the global energy crisis largely results from continued dependence on fossil fuels and underutilization of renewable resources. Fossil fuels such as coal, petroleum and natural gas release energy through combustion, an exothermic reaction that emits greenhouse gases. Natural gas, like petroleum, is a mixture of hydrocarbons, primarily methane, along with smaller amounts of ethane and propane and impurities such as sulphur compounds. In contrast, alternative energy sources—hydroelectric power, biomass, biogas, wind, tidal, geothermal and solar—offer substantial environmental benefits. Environment-friendly fuels are relatively safe to store and transport, do not emit greenhouse gases and can generate significant amounts of energy without polluting the environment.
In Pakistan, the dumping of industrial and agricultural waste, coupled with inadequate sewage management, has led to severe surface water pollution. This problem is particularly acute in major cities such as Karachi, Lahore and Faisalabad. Rivers have become unsafe, carrying untreated sewage. For example, approximately 2,000 cusecs of untreated sewage from Lahore are discharged into the River Ravi. Pakistan’s extensive archaic irrigation system infrastructure has also resulted in waterlogging and salinity, affecting nearly 3.5 million hectares of farmland. Furthermore, the Indus Basin’s reliance on glaciers in the western Himalayas makes the country’s water supply increasingly uncertain in the face of climate change.
The global supply of fresh water has already declined by 3% of the average annual supply, worsening the situation. Pakistan ranks fifth among 23 most water-insecure countries facing climatic risks. Water scarcity threatens food security, while floods and droughts force migration from vulnerable regions. Rising demand stems from population growth and irresponsible use. Effective conservation and equitable distribution among agricultural regions are essential for resolving disputes and ensuring sustainability. Upstream water saving positively impacts downstream flow, particularly for the Indus Delta. Freshwater is vital for delta fertility and preventing sea intrusion. Protecting water and air from pollution is fundamental to public health, ecological safety, economic stability and the future of life on Earth.
—The writer is Professor at Pakistan Study Centre, University of Sindh.
