Residents of the small village of La Villita in the Jalisco municipality of Tala were woken in the early hours of Sunday morning by a fierce odor of gasoline that burned their throats and made their heads ache.

Drug gangs are said be pleased as they assess the windfall President Enrique Peña Nieto has handed them by opening Mexico’s 75-year-old state oil company, Pemex, to foreign investors, putting up for grabs this country’s portion of the rich Eagle Ford Shale deposits.