I found this photo floating around teh internets which may or may not be the reason for the fare hike.
Not to be outdone, there are rumours that CityCab is also planning a new surcharge for customers who want to be the Elite of Elite Taxi customers.
Soon you will see the pre-peak taxi surcharge, pre-midnight-disappearance surcharge, the driver-lunch-hour & changing shift surcharge.
My other predictions:
2012: "Comfort Del-Groan Taxis is pleased to announce that the new surcharge-less period of the day is now 2.15pm to 3.15pm."
2013: "Comfort Del-groan Taxis is pleased to announce that there will be no fare surcharge on days beginning with "G"."
2014: "Comfort Del-groan Taxis is pleased to announce that there will now only be two surcharges: peak and more-peak."
(In case you are wondering, these are NOT real photos of Singapore cabs but are cleverly photoshopped images by witty internet persons.)