In 1959, Emperor Hirohito's older son, Akihito, became the first man in the imperial family to marry a commoner. Television broadcasting had begun in 1953. Citizens who wanted to watch live coverage of the wedding parade rushed to buy receivers; a huge increase in ownership meant television began to play a major role in Japanese daily life. As the Cold War continued, Japanese engaged in heated, sometimes violent, disputes over whether their country should renew its security treaty with the United States. Eventually, the political turmoil subsided and the economy rose. In 1960, the Prime Minister pledged to double citizens' incomes in 10 years. The economy actually grew four-fold over that period. Migration of people from rural areas to big cities caused urban problems such as rush-hour traffic. Pollution showed that the priority placed on economic growth was straining the environment.