Bhutan's sixth Five-Year Plan (1987–92) included a policy of 'one nation, one people' and introduced a code of traditional Drukpa dress and etiquette called ''Driglam Namzhag'' . The dress element of this code required all citizens to wear the ''gho'' (a knee-length robe for men) and the ''kira'' (an ankle-length dress for women). A central plank of the Bhutanese government's policy since the late 1960s has been to modernize the use of Dzongkha language. This began with abandoning the use of Hindi in 1964; a language that was adopted to help start formal secular education in the country. As a result, at the beginning of the school year in March 1990 the teaching of Nepali language (which share similarities with Hindi) spoken by ethnic Lhotshampas in southern Bhutan was discontinued and all Nepali curricular materials discontinued from Bhutanese schools.