Please answer a question about the following article about Carnival:

Peruvian Carnival incorporates elements of violence and reflects the urban violence in Peruvian society following the internal conflict in Peru. Traditionally, Peruvian Andean festivities were held on this period every year because it is the rainy season. It was already violent during the 19th century, but the government limited the practice. During the early 20th century it consisted partying and parading, while in the second half of the 20th century it acquired violent characteristics that continued. It was banned, first from the streets in 1958 and altogether in 1959 by the Prado government. It consisted basically of water battles in a traditional way,[clarification needed] while in later years it included playing with dirty water, mud, oil and colorants -and also including fighting and sometimes looting private property and sexual assaults on women. It has become an excuse for criminal gangs to rob people while pretending to celebrate. As of 2010, it had become so violent that the government imposed penalties of up to eight years in prison for violence during the games (the games themselves are not forbidden, but using violence during the games or coercing others to participate is).

When did the festivities acquire their violent tendencies?
second half of the 20th century