being run in two parts. It was stopped around mid-distance when Briton Derek Warwick crashed heavily coming out of the Peraltada. Brazilian driver Nelson Piquet finished first on the road, but because his Williams teammate Nigel Mansell was 30 seconds ahead when the first race ended, Mansell kept Piquet in sight and won the race on cumulative time. The 1988 race was moved from mid-October to a warmer and more rain-prone late May season slot, so that it could be paired with the other North American Grands Prix in Montreal and Detroit. This race saw Frenchman Alain Prost dominate in his McLaren, and Prost's Brazilian teammate Ayrton Senna won the next year; this was at a time when the two men's relationship was at a low point. 1990 saw the race moved to late June. Prost, now at Ferrari, qualified 13th on the grid but drove through the field, and took second from his teammate Mansell late in the race. Senna, who was leading, had a slow puncture that turned into shredded rubber and he went into the pits to have it changed, but the suspension was too badly damaged for the Brazilian to continue. This put Prost and Mansell 1–2 but Senna's teammate Gerhard Berger was challenging Mansell for second; Berger passed the Englishman going into the Moises Solana esses, but Mansell repassed him around the outside of the Peraltada on the same lap. Prost won the race; Mansell and Berger finished second and third. 1991 saw Senna crash heavily at the Peraltada during practice; he was declared fit to race by FIA doctor Sid Watkins; he finished third behind Williams drivers Riccardo Patrese and Mansell; but Senna had been critical of the severely bumpy circuit all of that weekend. On 9 October 1991 European media sources reported that promoters barely made enough funds to pay off F1 for the 1991 race. FISA demanded improvements to the track for the 1992 event, which were made. For the 1992 season, the race had been moved further forward to March, and on 20 February of that year, Mexico City's air pollution had reached a record level. City officials had imposed emergency measures banning half of government cars and equipment from the streets; this was not helped by the fact that Mexico City is situated in a valley surrounded by mountains, which restricts polluted air to travel elsewhere to dissipate. This put