The term blighty is basically British English, which is considered to be a slang term for Great Britain. This word comes from the Hindustani word, bilāyatī, which literally means "foreign". This word is also very much related to the Arabic word wilayat, which means a kingdom or province. This term was much more popular in the later days of the British Raj reign.
According to World Wide Words, Sir Henry Yule and Arthur C Burnell, have explained in terms of the Anglo-Indian dictionary, which is the Hobson-Jobson, published in 1886, that this very word existed in British India fro may of the various reasons like the tomato (bilayati baingan) and soda water, which was usually called bilayati pani, or "foreign water".
According to World Wide Words, Sir Henry Yule and Arthur C Burnell, have explained in terms of the Anglo-Indian dictionary, which is the Hobson-Jobson, published in 1886, that this very word existed in British India fro may of the various reasons like the tomato (bilayati baingan) and soda water, which was usually called bilayati pani, or "foreign water".