Group photographs are great because they give an actual sense of what people wore back in the day.
The first pic for example is probably Madras in the 1930s. All the women are in the then modern six-yard sari. The pallu at this point in Tamil Nadu was normally tucked in (a hangover from the older nine-yard sari?) or draped over the shoulder, leaving it loose in the current fashion was frowned upon by traditionalists. On the men, the dhoti and angavastram (literally cloth for the body and more or less a shawl cum scarf) set has ancient roots, the shirt or kurta was added on in mughal/colonial times. The coat likewise was added on, like the modern blouse it served as an incorporation of a Western element. I think the male headgear here is from Maharashtra (the black conical version) – there is a reference in one of the texts I read to “black velvet Gandharwa caps” which were one of the first sartorial statements in Poona – and Mysore (the white turban). The coloured turban (second from left, seated row 2) is probably similar to those worn by Gujaratis in the west of India but I can’t say this for certain.
Pic 2 is probably from the 1940s and includes a few spunky ladies involved with the freedom movement. In the first seated row of women and in some of the men, you can see the Tamil attire discussed above. The second seated row of women are probably Gujarati given the style of wearing the sari. I think Kasturba Gandhi is also in the pic.
Pic 3 is a group photo of students of Kinnaird Collge for Women, Lahore. Probably taken late 1920s (McNair was appointed Principal in 1928) or early 30s. At this point the six yard sari was modish so its not surprising to see so many of the Lahori students wearing it. Two of the women are in salwar kameez.
Pic 4: Sgt. Carl W. Ritter does a roundup of the “Vassar of the Orient” (Lady Irwin College, Delhi) on 7 Feb 1946. More pics at the link. The students seem to be from many states, including the South. As for the attire, there is the modern sari, the salwar-kameez and also a girl in a sari worn Bengal style.