Shivangee Misra, Anirban Sanyal and Sanjay Singh have this very useful paper summarising seasonality in Indian data:
This article provides estimates of seasonal factors of key economic indicators in India, analysing 78 monthly indicators across six sectors — monetary and banking, payment systems, prices, industrial production, merchandise trade, and services — along with 25 quarterly indicators. Latest estimates of seasonal factors (corresponding to 2023-24) are provided in the form of detailed tables.
Highlights:
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- Overall, seasonal pattern remains mostly stable across major economic variables although seasonal variations have become more pronounced across several indicators such as cash in hand and balances with the RBI, demand deposits, prices of major vegetables, industrial production, passenger vehicle sales, and merchandise exports.
- CPI faces seasonal pressure from July to November, mainly driven by rising vegetable prices during the monsoon season, while fruit prices tend to peak in the summer months.
- In industrial production, most items reach their highest levels in March, whereas consumer durables see a peak in October, coinciding with the festive season.
- Both exports and imports also peak in March, with exports exhibiting more pronounced seasonal fluctuations compared to imports.
- Quarterly data highlight increased seasonal variation in real GDP, especially in government expenditure, with agriculture showing the most significant seasonal effects. Capacity utilisation in manufacturing peaks in the January–March quarter, which also coincides with a rise in services exports.
- Among the quarterly series, real GDP and GVA continue to record their seasonal peak during Q4. The seasonal variations in the national accounts aggregates have increased since the onset of the pandemic, even after adjusting for the pandemic-induced volatilities.
Very useful summary…
Mostly Economics 
