Case 1: The sewerage water has stopped, but can flush manually by directly pouring water from water buckets.
Fill water in a bucket and flush. Water can be used more efficiently when directly flushed, than storing water in the toilet water tank.
For urine, flush once in several times. For feces, throw away the toilet paper separately to avoid clogging.
Case 2: When toilets are completely unavailable.
Do your business into newspapers. Fold it up and throw away in the garbage bag.
Try using minimum amount of toilet papers, then dispose in a separate plastic bag.
Dispose toilet papers on fire, if there are collective garbage combustion fires around you.