The NSE website has PE (Price to Earnings), PB (Price to Book) and Dividend Yields of indices going back a decade. Even though their methodology of calculating these has its drawbacks, they are consistently applied to all the indices. This makes an apples-to-apples comparison possible.
In the next part, we will explore if these can be used to time or switch between large-caps and mid-caps.
Code and charts on github.