These are the Dirtiest hotels in Asia Pacific, as reported by Trip Advisor, based on TripAdvisor traveler reviews.
1.First Hotel, Bangkok, Thailand
2.Hotel Grand Central, Singapore, Singapore
3.The Imperial Hotel, Hong Kong, China
4.Royal Peacock Hotel, Singapore, Singapore
5.Woraburi Sukhumvit Hotel and Resort, Bangkok, Thailand
6.Colmar Tropicale, A French-Themed Resort, Bentung, Malaysia
7.Oxford Hotel, Singapore, Singapore
8.City Gate Hotel, Hanoi, Vietnam
9.Royal Parkview Hotel, Bangkok, Thailand
10.Aseania Resort, Langkawi, Malaysia
I have not had the pleasure of staying in any of these - unable to comment on the list accuracy. Perhaps, others can.
For othe continents, check the following link:-
http://www.tripadvisor.com/DirtyHotels?nl=MU&pid=1595