Dry Shampoo is more like a spray which you can use to refresh your hair mid-day or in between washes. I used to use it every other day between my washes. Now sometimes I use in the afternoon. The more well known brands are Batiste and Kloane. Both are available in Watsons.
Clarifying shampoo definitely helps, but be careful not to dry up your hair. I've attached a blog article on clarifying shampoos in Japan, but all three items are available in Singapore, so u can consider this as well.
you will need to use a shampoo to clear the oil on your scalp and also buy a hair treatment(eg mask or /treatment') 2x a week to deep cleanse the pores. Is important to wash your hair everyday and make sure it is blow dry because our weather is humid. I recover from it too