The SGST collection of 18 major states, on average, declined 9.67% in 2020-21 compared to 2019-20. However, Kerala's SGST collection fell 12% during the same period.
States on average lost 8.1% of TGST revenue between 2019-20 and 2021-21.  
Revenue growth of states recovered sharply in 2021-22. The state-wise average increase in the SGST collection was 25 per cent. Similarly, TGST revenue of states, on average, increased by 30.7%.
Kerala's TGST revenue grew at 27.8% in 2021-22 from a year earlier, less than the all-states average.
Comparing the revenue collection in 2021-22 with 2019-20 shows that in terms of SGST collection, all states, on average, have surpassed the pre-pandemic year level by 13 percent.
While Chhattisgarh and Gujarat exceeded the 2019-20 SGST collection by 20.0%, Kerala's revenue was up 4.6 percent.
On the other hand, all states were able to increase their TGST collection significantly, i.e., at least by 12 percent between 2019-20 and 2021-22. The all-state average increase was 20 percent.
This higher recovery in TGST collection compared to SGST is due to higher IGST growth.
Kerala surpassed the 2019-20 TGST collection by 16.4%.

Introduction
By eliminating various indirect taxes, improving the flow of goods and services, and reducing entry barriers at the state level, the GST implementation in India was an attempt at economic integration of the nation with the goal of enhancing trade and assisting the economy. The implementation of GST, thus, though not directly, was expected to accelerate the tax revenue of both the Union and State governments. This anticipation can be attributed to a simplified tax system and a reduction in the cost of compliance which would improve compliance and ease of doing business, thereby generating a huge thrust in the country's economic activities. But the Indian economy was already in a plaintive state due to the demonetization of 2016, and GST was implemented before the economy could regain its pre-demonetization growth momentum. It was like jumping out of the frying pan into the fire when COVID -19 struck the country in the early months of 2020. The pandemic emaciated the economy more than any other issue. The consumption of people shrunk during the pandemic, adversely affecting the GST collection of states.
But recent GST collection figures are encouraging and display some confidence in the stability and recovery of collections. The gross GST collections in the month of August touched Rs 1.43 lakh crore, 28 percent higher than the corresponding month of 2021. This was the sixth month in a row where the monthly collections have been more than Rs 1.4 lakh crores, indicating the strong recovery of GST from its low points during the pandemic. Though the collections at the aggregate level have been satisfactory, analyzing at the state level may tell a different story about the pace and robustness of recovery.
This paper aanalyses the magnitude of the fall in GST revenue of states during the pandemic and assess the recovery in the collection of states in the post-pandemic phase. To this end, we compare the recovery of GST revenue in 2021-22 with the previous year (2020-21) and the pre-pandemic year (2019-20). While a comparison of GST in collections between 2021-22 with 2020-21 tells us to what extent the states have recovered, comparing collections in 2021-22 with 2019-20 would indicate whether the states have surpassed the collection recorded in the pre-pandemic year.
Data sources and variables
This study considers two aspects, namely State GST (SGST) and Total GST (TGST) collection, to assess the revenue performance of the states. SGST refers to the State Goods and Services Tax collected by the states on intra-state transactions of goods and services. TGST refers to the total collection of the states. It is the sum of SGST collection and IGST settlement revenue. The IGST collected by the Centre is shared with the state where the goods or services are sold and not the state where the production happens. TGST is the actual revenue of the states. 
Eighteen major states are considered in this study. Monthly data sourced from the GST portal (https://www.gst.gov.in/download/gststatistics) is added to get the yearly numbers. The study period is from 2019-20 to 2021-22. 2019-20 is the pre-pandemic year, 2020-21 is the pandemic year, and 2021-22 is the recovery or post-pandemic year. The collections of the three financial years have been compared to analyze the revenue performance of the states during these years. 
The pandemic year: Revenues plummeted
Table 1 exhibits the annual revenue collection of states for the years 2019-20, 2020-21, and 2021-22 (Columns 1-3), along with their growth rates (Columns 4-6). Column 4 reports the percentage change in 2020-21 (pandemic year) over 2019-20 (normal year); Column 5 presents the percentage change in 2021-22 (recovery year) over 2020-21 (pandemic year), and Column 6 shows the percentage change in 2021-22 (recovery year) over 2019-20 (normal year or pandemic year).

Table 1: SGST revenue collection of states

Dash, S.K., & Kakarlapudi, K.K. (2022). What explains interstate variation in GST collection? Gulati Institute of Finance and Taxation, Working Paper – 02/2022.
The Hindu (2022). Price rise driving 8% of GST revenue surge: SBI Research, August 5, 2022. Retrieved on September 6, 2022. https://www.thehindu.com/business/price-rise-driving-8-of-gst-revenue-surge-sbi-research/article65727203.ece.