Rebellious crowds of people in a rural area in central Mexico are defying police and soldiers by stealing diesel from illegally tapped pipelines, creating the potential for fires that have burned dozens of people elsewhere in the country. A recent video showing a crowd using buckets to collect diesel from a huge makeshift pool in the state of Tlaxcala exemplified the trend in pipeline thefts, which rose 52% in 2015 to reach a rate of nearly 15 illegal taps a day across the country. Alejandro Espejel, the spokesman for the city of Calpulalpan, said people in several villages have made a habit of either perforating pipelines or taking advantage of taps created by professional fuel thieves. They have broken through security perimeters on almost two dozen occasions in the last year, built dams to create diesel-containment ponds and hauled up fuel by the bucketful to sell. Mr. Espejel said the villagers have defied orders by police and security authorities to stop the practice.