I've been looking at option chains on websites for some popular exchanges (NSE, etc). The exchanges usually provide an implied volatility column in their data, where they're presumably calculating the Black-Scholes or Black76 implied volatility quotes.
The implied volatilities for puts and calls are different despite these being European options (and so violating put call parity). Why is that the case?
As an example, see the IV column from an options snapshot on the NSE: https://www.nseindia.com/option-chain . The IV is not the same for calls and puts of the same expiry and underlying, despite options on the NSE being European style. The IV column shows quite significant differences between calls and puts.