MYSQL: Error Code: 1366. Incorrect string value: ‘\xE0\xA4\xAA\xE0\xA5\x8D…’ for column

While trying to modify Max-length of column ‘Phone’ in MySQL Database, I got this error:-

(Error Code: 1366. Incorrect string value: ‘\xE0\xA4\xAA\xE0\xA5\x8D…’ for column ‘Phone’ at row 26691)

STATEMENT:-
ALTER TABLE User_Base MODIFY COLUMN Phone VARCHAR(50) NULL;

Initially I was surprised seeing this error. But later I noticed that datatype of column was ‘NVARCHAR’ & I was trying to change it to ‘VARCHAR’. Since data was invalid for ‘VARCHAR’ type it threw the error.