SINGAPORE - In determining whether Grab's acquisition of rival ride-hailing firm Uber is bad for consumers, the Competition Commission of Singapore and the Land Transport Authority have their work cut out for them.

First of all, unlike the proposed (and now, irrelevant) alliance between taxi giant ComfortDelGro and Uber, the Grab-Uber deal is extremely difficult to undo. Even if it is deemed anti-competitive - which is far from clear cut - disallowing it here would lead to just one ultimatum to Grab: Scrap the deal or leave the local market.