Which came first, email or Pakistan?

Pakistan came first, by 24 years. Pakistan became independent at midnight, one day before India.

Side by side

email

Messages had been left for other users of the same machine since the mid-1960s. What Tomlinson did in 1971 was send one between two different computers on ARPANET, and pick @ to separate the user from the host because it was the only preposition on the keyboard that could not appear in a name. He did not record the first message and later said it was probably "QWERTYUIOP" or similar. Email is eighteen years older than the Web.

Pakistan

Pakistan and India were created by the same act of parliament, but Mountbatten had to attend both ceremonies, so he took the Pakistani one in Karachi on 14 August and the Indian one in Delhi on the 15th. Pakistan is therefore one day older than India in the sense the question means. Independence in both cases took effect at the same instant: midnight between the two dates.