Introduction:
Urbanization refers to the process of population shift from rural areas to urban areas, resulting in the growth of cities and towns. However, unplanned urbanization can have detrimental effects on the environment, particularly on water resources. This response will outline how unplanned urbanization contributes to water pollution.

Increased Land Development:
Unplanned urbanization often leads to rapid and haphazard land development, resulting in increased impervious surfaces such as roads, parking lots, and buildings. This has several negative impacts on water quality:

1. Stormwater Runoff: With the increase in impervious surfaces, rainwater cannot infiltrate into the ground, leading to excessive stormwater runoff. This runoff collects pollutants such as oil, chemicals, and debris from roads and urban areas. It eventually enters water bodies, causing pollution.

2. Sedimentation: Unplanned urbanization disturbs natural soil and vegetation cover, leading to erosion. This erosion results in sedimentation, where soil particles are washed into rivers, lakes, and streams. Sedimentation reduces water clarity, disrupts aquatic ecosystems, and can harm aquatic organisms.

Wastewater Discharge:
Unplanned urbanization often lacks proper infrastructure for wastewater management, leading to the discharge of untreated or poorly treated wastewater into water bodies. This contributes to water pollution in several ways:

1. Pathogens and Disease: Untreated wastewater contains harmful pathogens, including bacteria, viruses, and parasites, which can cause waterborne diseases like cholera, typhoid, and hepatitis. These pathogens pose a threat to public health.

2. Nutrient Pollution: Wastewater contains high levels of nutrients, such as nitrogen and phosphorus, which can cause excessive growth of algae and other aquatic plants. This leads to eutrophication, where water bodies become over-enriched, depleting oxygen levels and harming fish and other aquatic organisms.

Industrial and Commercial Activities:
Unplanned urbanization often leads to the establishment of industries and commercial activities without proper environmental regulations. This can result in the discharge of hazardous chemicals and pollutants into water bodies, contributing to water pollution.

1. Chemical Contamination: Industries may release pollutants such as heavy metals, organic compounds, and toxic chemicals into water bodies. These contaminants can accumulate in aquatic organisms, entering the food chain and posing risks to human health.

2. Oil Spills: Unplanned urbanization often involves increased transportation activities, including shipping and oil pipelines. Accidental oil spills can occur, releasing large amounts of oil into water bodies, leading to severe ecological damage.

Conclusion:
Unplanned urbanization significantly contributes to water pollution through increased land development, stormwater runoff, sedimentation, wastewater discharge, and industrial activities. To mitigate these negative effects, it is crucial to implement proper urban planning measures, including sustainable land use, proper wastewater treatment infrastructure, and strict environmental regulations for industries and commercial activities. This will help preserve water quality and safeguard aquatic ecosystems for future generations.