Remove space between sections in collectionview

How to adjust the spacing between sections of collection view.

Header height can be adjusted by adjusting the params of the collection view layout. Following is the code which works perfectly fine.

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section 
{
    if ([[sectionHeaderArray objectAtIndex:section] boolValue]) {
        return UIEdgeInsetsMake(10, 10, 10, 10);
    }
      return UIEdgeInsetsZero;
}