#!/usr/bin/perl

use strict;
use warnings;

my $file = '/path/to/file.csv';

open my $fh, '<', $file or die $!;
while( my $line = <$fh> ){
    my ($id, @array) = split /;/, $line;
    print $id, ";", $_,"\n" for grep{ defined }@array;
}
close $fh;