At a packed festival in central Jakarta, hijab-clad sexagenarian singer Rien Djamain bursts into an upbeat track about nuclear destruction to a crowd of thousands, mostly young Indonesians.

Behind the frontwoman of the all-female Nasida Ria band are her fellow musicians, dressed in silver and black sequined dresses, backing up her velvety vocals with bongos, violins, mandolins, bamboo flutes and tambourines.