Strainer Placement

It seems a rough language question. The location may be Up-Stream or Down stream but not above or below the Shut-off valve. Strainer is always provided at down stream of Shut-off valve so that same can be cleaned after isolation of pump.

In my opinion, it is always better to place a strainer downstream of the pump.

Tthe reason for this preferred placement is that there is less chance of pump starvation and cavitation when the strainer fills up

This, of course assumes that your expected particles can pass through the pump.

If you expect large particles and possible pump clogging, clean your tank, consider a sump within the tank and strain any particles before the liquid enters.

Your last and least desired option is a strainer upstream of the pump.

Pumps internal clerances are normally very small in values. Any particle bigger then half of the size of total radial clearance can damage your pumps and the next step will be costly overhauling of the pump not the cleaning of the strainer.