The Punjabis of West Pakistan and the Bengalis of East Pakistan are divided by history and culture as well as by 1,000 miles of territory. The division lies behind the political ferment that has been growing in recent months and last week threatened a breakdown in Pakistan's governmental process.

The 55 million Punjabis, a dour and martial people, dominate the central Government in the country's western wing. The more emotional Bengalis in the East contend that the greatest share of industrial development has gone to West Pakistan even though the East has more people, 75 million, and they regard the largely Punjabi army as virtually a foreign occupier.

Pakistan has been ruled under martial law since Gen. Agha Mohammad Yahya Khan assumed the presidency in March, 1969, after the overthrow of President Mohammad Ayub Khan. Elections were held last December for a National Assembly that would draft a constitution to return the country to civilian rule. The Assembly was scheduled to open last Wednesday, but President Yalya postponed it “with a heavy heart” because of a “political confrontation.”

The postponement triggered a general strike and riots in Dacca, East Pakistan, forcing the central Government to send in troops to impose security measures.

The crux of the controversy was the demand for a measure of autonomy by the Bengalis, led by Sheik Majibur Rahman whose Awami League won an Assembly majority, in the December elections. The demand was opposed by Zulfikar All Bhutto, a former Foreign Minister who heads the principal West Pakistani party, the leftist Pakistan People's party.

At the end of the week, President Yahya held talks with the opposing sides in an attempt to reconcile their differences.