Need solution to clear muddy water discharge from borewell


Two years back a bore well was dug, 200 feet deep with water source at 150 feet, but we also gt silt and mud. We dug a little deeper and stopped at 250 feet. PVC and  steel casing was provided upto 95 feet. Slotted pvc pipe of 5inch size has been inserted separately upto a depth of 125 feet. 1 hp submersible pump was installed at 122 feet and clear water was used for construction of new house for about 15 months.

We were getting 1000 litres clear water at a time for construction and we could fetch water for one hour continuosly.  Since one week we are gettting muddy water from the borewell. The pump is functioning properly  and over head tank is getting filled automatically, but with only muddy water.

We have aso erected rainwater harvesting structure -2 feet wide, 20 feet deep tank with concrete rings adjacent to the borewell 8 months ago.

Please tell me what could be the reason for discharge of muddy water and also possible remedy to get clear water