Phosphate pollution is caused by _______.

Hint: The agricultural fertilisers are checked for quality by the ratio of NPK in them, where N stands for Nitrogen, P stands for Phosphorus and K stands for Potassium respectively. This fertilizer is then discharged into soil as well as water bodies after the harvesting of crops.

Complete answer
Phosphate is crucial for plant growth and development, and it's estimated that half the world’s food supplies are dependent on phosphate fertilisers, but this is often a dwindling resource that's used very inefficiently, which is resulting in widespread pollution. Unlike nitrate, phosphate binds very strongly to the soil, which makes it difficult for plant roots to hold it. Then farmers apply even more phosphates in fertilisers and manure, although much of that phosphate then sticks to the soil again, driving the amount of phosphate within the soil even higher.
When phosphorus is slowly released into the soil water, much of it washes away by itself. The phosphorus pollution is reaching dangerous levels in streams, rivers and other waterways, resulting in big blooms of algae that swamp wild aquatic plants and starve fish and other aquatic creatures of oxygen. But work on Reading University is hoping to use bacteria within the soil to interrupt down the unused phosphorus, boosting crop growth and reducing waste.

Note:
The phosphorus in the fertilisers is taken into two categories while evaluating the amount present in the fertilisers, namely Total Phosphorus and Available Phosphorus for the plants. Nitrogen is calculated as Nitrate and Ammonia in the fertilisers.