‘Slag heap’ means garbage dump. The poet is pointing at the children of the slum who are extremely starved and malnourished. They appear skinny like a skeleton. Their world is full of dirt and garbage and they spend their life raking these slag heaps.
The poet’s smile in the poem ‘My Mother at Sixty-six’ shows that she is trying to pretend that everything is alright. She is trying to comfort herself and her mother by putting on a brave front.
There are two worlds that Anees Jung is referring to in the context of Mukesh, the bangle maker’s son. One world is of the family, caught in poverty and burdened by the stigma of caste in which they are born. The other world is the vicious circle of the chukars, middlemen, policemen, keepers of the law, bureaucrats and politicians.