my $phash = \%Tech_fy_reldata;  # Assign to hash reference (eg. \%hash)
while(<NEW>){
    @val=split /\t/;
    foreach my $val (@val) {
        my $pvalue = $phash;  # Start with reference to hash
        if (CONDITION1) {
            $pvalue = $pvalue->{KEY1};  # Down 1 level
            if (CONDITION2) {
              $pvalue = $pvalue->{KEY2};  # Down another level
              # ... etc ...
            }
        }
        $$pvalue = VALUE;  # Use $$ to dereference for assignment
    }
}

##</code><code>##

        $$pvalue = VALUE;  # Use $$ to dereference for assignment