Zip validation for Indian Pincodes is incorrect.

The zipcode validation for indian pincodes has the following

//zip code is 6 digits with a possible space after third. first set is 1-9, second is 0-9

This is incorrect. 400056 is a valid pincode and it will fail the preg_match

preg_match("^[1-9]{3}\s{0,1}[0-9]{3}$", $item['zip'])

the correct validation should be
//zip code is 6 digits with a possible space after third. first digit is 1-9, next 2 digits are 0-9, followed by an optional space and 3 digits in the set [0-9]
and the preg_match would be

preg_match("/^[1-9]{1}[0-9]{2}\s{0,1}[0-9]{3}$/", $item['zip'])