1. The capital of Pakistan, following its independence in 1947, was initially Karachi, the large port city on the Arabian sea, near the mouth of the Indus river in the southern province of Sindh. With the increasing dominance of the Panjab, the capital was shifted first, in the early 1960's, to 'Pindi (Rawalpindi) in the north, where the Panjab plain meets the Himalayan foothills, and what was then the NWFP (North West Frontier Province), inhabited by Pathans (Pashtuns/Pakhtoons)) and others. Around 1966, it was moved to the neighboring, newborn, planned capital city of Islamabad. So Islamabad was the official capital at the time of what was essentially a military coup, in March of 1971, against what would have been the newly elected government led by Mujibur Rahman's Awami League, which had its base in mainly Bengali-speaking East Pakistan, separated from W. Pakistan by well over a thousand miles by the width of the Republic of India.
The brutal crackdown by the Pakistani army, starting in March of 1971, in that eastern wing of Pakistan, the stirring up of religious animosities, and the ever-present scarcity of land and resources in the fertile but overpopulated delta region, led to a great number of hapless, frightened, malnourished and footsore refugees streaming across the borders into neighboring states in India (which I witnessed first-hand as a relief worker there) and quite a bit of local resistance, including from a lightly-armed guerrilla force, the Mukti Bahini (Liberation Army). Most of the Awami League leaders, however, those not arrested along with Mujibur Rahman, fled across the border to Kolkata. The final full-scale war, involving the Indian army, that led to the creation of Bangladesh, occurred at the end of 1971.
Although Islamabad was then the capital of Pakistan, I have referred to 'Pindi in the verse line, as that was where much of the W. Pakistani army headquarters and generals were centered. The two cities are situated, I believe, cheek to jowl. I gathered then, from talking to many of the refugees (mostly Hindu, but with a fair number of Muslims as well) that the lot of ordinary peasants, especially the landless ones, might not change that much if and when the W. Pakistani rulers, reigning from Islamabad-Rawalpindi, were exchanged for Bengali ones ruling from Dhaka, just as the departure of the British had, at least at that time, left much of the peasantry unaffected all over the subcontinent, still subservient to, indeed, effectively enslaved by, the feudal landlord hierarchy that had been established since before the Mughals.
For me, this was a revelation, which I might not have had had I not journeyed, in the summer of 1971, full of youthful idealism and misplaced Bengali nationalism, 900 miles southeast by train with a Gandhian group from Dilli to Bongaon, a small town on the Ichamati river, which separated the eastern Indian state of W. Bengal from what was then E. Pakistan. But after talking to the refugees (many of whom had received their only organized help, on their own side of the border, from the Communist Party and the National Awami Party) and after rowing surreptitiously across the Ichamati, as cannon boomed, to visit a badly shelled and nearly abandoned village, where we met a few remaining aged inhabitants and some wary youths who were part of the local Mukti Bahini, I came to this conclusion, which was, at the time, a rather sad and life-changing one for me. I hoped then that I would be proved wrong.
2. The reference is to the British East India Company, and to the Uprising of 1857 in the subcontinent, led by the native sepoys (soldiers) employed in the Company's army. The rebellion was brutally suppressed. However, the British Crown then took direct control of India, making it a centerpiece of the British Empire, taking a slightly longer view and shrewdly reining in, to some degree, the rapacity of the colonial enterprise there.
3. Howrah is a suburb of Kolkata (Calcutta), in the state of W.Bengal, India. It houses the main railway station and is linked to Kolkata by the Howrah Bridge, built in British times across the Hooghly river, a broad local estuary of the Ganges, navigable by ocean-going ships.
4. Sylhet is a north-eastern district of Bangladesh, bordering the Indian states of Meghalaya, Assam and Tripura. It is a lush, hilly region, with tea, oil and gas being major industries. Sylhet, like a few other parts of the subcontinent, has long had a large expatriate population, many of whom work in the U.K. and in the Gulf states, sending remittances home.