After arrival check-in around 3pm we were out the whole afternoon and when we return to our room around 9pm we smelled a strong stench from the toilet. I had to call front desk to enquire about the sink problem and a plumber came but was unable to rectify. We were later inform by the duty manager that they had plumbing problem on that particular block and had known about this early during evening room turn down. We were than told we had to change room after 10pm.