If you want, then replace line 508 in the CoA:

  `curr_symbol` varchar(10) NOT NULL DEFAULT '',

with whatever encoding you want - please note that the one of the first lines has SET NAMES latin1; as the default encoding.

Also change the data in line 521 accordingly for the symbol besides saving the file as UTF-8 encoding text and change the _init/config file with the proper encoding.

Currency Abbreviation: INR
Currency Symbol: Rs. or INR
Currency Name: Indian Rupees
Hundredths Name: Paise
Country: India

If you really need ₹ as only option then open phpmyadmin select table 0_currencies under SQL write this query and GO

Please Note: 0_ is the default prefix of primary company. Replace with your company's prefix.

ALTER TABLE 0_currencies MODIFY COLUMN curr_symbol VARCHAR(10)
    CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '';

Now Try Inserting ₹ symbol, it must get updated