Every morning, scores of people of all ages gather at Hoan Kiem Lake to do physical exercise that looks like child’s play. Forming lines or circles, they wave, clap their hands, and laugh cheerfully. Passer-bys often wonder what they are doing. They are practicing Laughter Yoga.

Every year, the members of Hanoi-based 3R Club, a non-profit club that promotes the reduce-reuse-recycle concept, holds a regular “Mottainai Fair”, inspired by the Japanese events in which people gather to exchange used items, instead of throwing them away wastefully.