In many places you cannot or should not put toilet paper down the toilet because the pipes used in buildings are a small diameter and the toilet paper will clog them up. However in some newer structures (like the new airport in Quito) larger pipes are being used and you are actually asked not to throw toilet paper in the trash, but to flush it. When we had our house built we had the larger pipes used and we’ve had no problems with with flushing toilet paper in the two years since.