This is indeed such a ridiculous rule - but that's how it is in most countries in Asia - another example of stupidity is Thailand - in so many of my trips, never really realized how un-educated/informed they are about powerbanks. For one of my last trip, first time bringing a power bank - and during transit, it was indicated outside that it should not exceed X amount of storage capacity, but any without such information will be consficated - and mine because of usage, the printed information on the case was all gone, so it went into the bin. It was obvious that it was so small and flat that it would be way below the stipulated capacity but no such logic used.

I wonder how these airlines all can join the IATA if they are so backwards in their mindset.

Cheers!