If you have enough money to pay the traffickers, you can get a spot in the open air on the deck, and maybe even be allowed to wear a life jacket, which takes up precious, expensive room. Everybody else is relegated to the hold and diesel fumes -- locked in -- for the duration of the sea crossing. This usually means the hold is filled with women and children , who earn less and can pay less to the traffickers.
Italian authorities intercept clandestine migrants on the Mediterranean, and rescue them. Photo by Massimo Sestini from The Guardian.