Singapore students are trained in school to return their trays after their meals ("S'pore diners still fare poorly in returning trays"; Monday).

Certainly, it does not mean that they are expected to do so only within their school canteens.

Just visit a few fast-food outlets in Bishan's Junction 8 mall, which is close to several schools.

Many students have their meals in these fast-food outlets after school. But it is uncommon to see the students clearing their tables and returning their trays.

This suggests that those students return trays in their schools only because they have to, without understanding the environmental reason for why they should do it.

Schools need to do more and explain to their students that they are expected to return their trays, not just in their school canteens but also when they dine in public eating places.

Oei Khoen Hwa (Ms)