The correct answer is stress on the environment. Explanation & Key Takeaways: • Higher population density in cities increases resource consumption, leading to a strain on natural resources such as water, air, and land. • Urban areas like Delhi experience elevated levels of air pollution due to increased vehicular emissions and industrial activities. • Overcrowding and rapid urbanization cause improper waste management and disposal, contributing to environmental degradation. • High population density results in deforestation and encroachment on green spaces to accommodate housing and infrastructure needs. • Excessive human activity in densely populated cities disrupts ecological balance, impacting biodiversity and ecosystem services. Related Concepts: • Population Density: • It refers to the number of people living per unit area, typically measured in persons per square kilometer. • High population density can lead to increased demand for housing, transportation, and public services. • Environmental Stress: • This term denotes the pressure exerted on environmental systems due to human activities. • Examples include pollution, resource depletion, and habitat destruction. • Urbanization: • It is the process by which rural areas transform into urban areas due to migration and infrastructure development. • Unplanned urbanization often leads to environmental challenges like water scarcity and air pollution. • Pollution Types: • Air pollution: Caused by vehicle emissions and industrial activities. • Water pollution: Results from untreated sewage and industrial discharge. • Land pollution: Caused by improper waste disposal and deforestation. • Sustainable Urban Development: • Focuses on creating eco-friendly cities with efficient waste management, green spaces, and renewable energy usage. • Encourages practices like rainwater harvesting and reducing carbon footprints.