Water pollution is caused by all the following except

Water pollution is not caused by sand filling. Sand filling, which involves the placement of sand in a specific area to fill in gaps or create land, does not necessarily involve the discharge of pollutants into the water. However, the other options listed - increased silt load, sewage disposal, industrial effluent, and mineral workings - can all contribute to water pollution. Increased silt load can lead to sedimentation, blocking sunlight, and reducing oxygen levels, which can harm aquatic life. Sewage disposal can introduce harmful bacteria and viruses into the water, which can cause diseases in humans and aquatic life. Industrial effluent can contain toxic chemicals and heavy metals that can damage aquatic ecosystems and affect the health of people who consume the contaminated water. Mineral workings can produce acidic runoff that can pollute nearby streams and rivers, killing fish and other aquatic organisms.