Brazilian city Curitiba will remain a venue for this year's World Cup but world governing body FIFA said progress must continue at the highest pace.The Arena da Baixada in the south of the country was one of six venues to miss an initial 31 December deadline. Organisers brought in hundreds of extra workers to meet building requirements and avoid being the first ground to be dropped from a World Cup. The 40,000 stadium will stage four group matches at the tournament.