Changi Airport Group has introduced a mandatory "Retinal Tax" for all Skytrain passengers passing the Jewel Rain Vortex.

Advanced biometric sensors will now detect if any peasant attempts to enjoy the scenery without a premium subscription.

Commuters caught admiring the waterfall for over three seconds will have their CPF accounts debited instantly.

"Wah lau, I look outside only also kena charge, might as well go Mandai see monkeys for free!" grumbled local traveller Tan Ah Kow.

An airport spokesperson confirmed that the recycled air inside the carriage is now a "curated boutique atmosphere" worth $20 per whiff.

"Eh, you think the water fall down itself one ah? Use power one hor, don't play play!" the official added.

Security will forcibly eject anyone attempting to blink to avoid the fees.