A general decline in economic activity, a contraction in the business cycle is known as recession. This decline in economic activity is spread over a few months, and there will be decline in industrial productivity, real income, real GDP, employment, etc. You can read about the Inflation in Economy- Types of Inflation, Inflation Remedies [UPSC Notes] in the given link.
Recession could happen due to pandemic, adverse supply shock, trade shock, financial crisis etc.
- Inflation Targeting: Methods, Drawbacks and Benefits
- Consumer Price Index (CPI) – CPI and its Types [USPC Indian Economy Notes]