How can an Indian architecture student get a scholarship/sponsorship for masters in National University of Singapore?

Speaking from my experience with Masters students during my internship at NUS, you don't need to apply separately for scholarships. They are getting more and more competitive, especially in the last couple of years after NUS's rank sky-rocketed.  Publications and conference presentations in your area of study should give you an edge. Almost all Masters scholarships come with a catch though. That you'll have to sign a bond of about 4 years and assure them that you'll work in Singapore for that period right after graduation. However, employment is HIGH there. So you won't have to worry about getting a job.