Financial data for Indian companies

For those wondering if there is an Indian counterpart to the SEC's EDGAR; yes, there is.

As of 27th December 2007, SEBI has decided to mandate filing through the new CFDS portal put in place jointly by BSE and NSE.
Over time, other modes of sending public information to stock exchanges for compliance with clauses of Equity Listing Agreement will be dispensed with, including filing through EDIFAR.

But financial data of more than 5 years is rare even on these official portals.
Corporate websites with the most comprehensive historical earnings and dividend data were:

Tata Steel [60 years of financial data]
Tata Power
Larsen & Toubro
J B Chemicals & Pharmaceuticals Ltd

Of other companies analyzed, the following have also provided useful data:

BONGAIREFN
HDFCBANK
COSMOFILMS
HINDALCO
RUCHISOYA
NMDC
TATAMOTORS
BHUSANSTL
HDFC
GAIL
SESAGOA
RELIANCE
GRASIM
ONGC
BHEL

Note that the presence of data in itself is not an indication to the quality of the stock.
The quality of a stock is a function of both its performance as well as its current price.
The implication here is that data such as that provided by the above companies makes the job of the analyst easier.