Yes, the Ganges Action plan was a success. It was a very small success, but it certainly wasn't a failure. The issue of Ganges river pollution, in my opinion, won't ever be "solved" in the traditional sense of word. I think that it is a dilemma, rather than a problem, lacking a real solution. However, I think success can be proclaimed when the current situation is improved upon and the negative consequences stemming from the pollution are mitigated. The Ganges Action plan was able to bring greater attention to the scale of pollution India is facing in this region. It also addressed the dangers of water-borne illnesses directly linked to the sanitation issues of Ganges river. So maybe, better said is, the Ganges Action plan was the impetuous of what could be success if those in power continue to act facts that the plan made available.
Aaaand Action! Ganges Action Plan that is