Some places where you can find the courts,
1. Safra ( Yes they still do have. I know for sure, Toa Payoh and Tampines)
2. Schools (NUS, NTU, most of the polytechnics and JCs)
3. Singapore Sports Council facilities
-Burghley Squash Centre
-Kallang Squash Centre
-St Wilfrid Squash Centre
-Yio Chu Kang Squash Centre
4. Private apartments. ( Ask around, see if anyone lives in a condominium equipped with squash courts)
It's a dying sport but it's NOT dead. There are still people actively involved, both playing ( leisurely and compeitively) and managing.
SSC is working towards reviving Squash by targetting the younger generation. All is not lost yet.