So stiff is competition between Indonesia's motorcycle taxis app companies that new entrants are going to extreme lengths to stand out.

Aris Wahyudi, the founder of the newest motorcycle-sharing company, thinks he has found a unique way to win business: not-so-smelly drivers.

"We took the decision to do an odor test for our customers' satisfaction," Wahyudi said, speaking in a sweltering basement car park, where prospective drivers are lining up to have their armpits sniffed as part of a selection test.