I have not comprised an exhaustive list of NGOs/foundations in Calcutta/Kolkata, India, but I was able to find a few resources that list and provide information about these types of organizations in Calcutta/Kolkata.
You have to be a subscriber to access the information on IndianNGOs.com, but it might be worth it to you as you can see from the following lists, which are pretty extensive...
NGOHome-Kolkata's focus seems to be specifically on NGOs in Calcutta/Kolkata. Though I didn't find any lists of NGOs on their Web site, they might be able to provide you with some useful information if you contact them directly. It seems one of their goals is to "give the smaller NGOs more visibility" (About Us page, para. 3).
Also, it was on NGOHome-Kolkata links page that I found, perhaps, the most useful link. That is for the Web site of ProPoor, self-described as "an internet portal that provides information, resources and news about development work in South Asia" (Home Page, para. 1). If you go to their database search page you will see that they have a category for NGOs. You aren't able to limit your search to individual cities, but you can limit it to State/Province. Calcutta/Kolkata is the capital of the West Bengal province/state. When I conducted a search for all types of NGOs in the West Bengal province/state, I retrieved 834 records. Of course, since we're able to limit the search only to the West Bengal province/state, a number of the NGOs listed in the search results are not in Calcutta/Kolkata, but just browsing through a couple of the pages, it seems most are. The search results contain links to pop-up windows which contain contact information (address, phone number, email) for the NGOs as well as Web site URLs, if available.
