Speaking to NDTV in the run up to the launch, Mr Debroy said, "This is not an ideal GST. There are too many rates, there are still exemptions. Both the positives that you hear about which are more in terms of ideal GST and the negatives that you hear about both are somewhat exaggerated."
He said a "proper GST" in most other countries has taken several years and that there are very few countries that have this tax regime. He said he was certain the GST Council would tweak certain aspects "as we go along".
But the launch, he said, should be applauded as "because it is the start of a process". "A lot of people did not expect this deadline to be adhered to because deadlines have come and gone in the past," Mr Debroy said.
The opposition, which had also participated in drawing up the GST, has criticized it on several counts - the main being that the country is not ready for it. Most parties will not be present for the midnight launch in Parliament's Central hall. Nearly 1,000 people are expected to present in the venue to witness the rollout.
Congress Vice President Rahul Gandhi, who is returning from a foreign trip, has tweeted that GST is being executed by an "incompetent and insensitive government without planning foresight and institutional readiness".