MILAN, Oct 2 (Reuters) - Delegates heading to the COP26 U.N. climate summit in Glasgow agreed they must deliver on the $100 billion per year pledge to help most vulnerable nations tackle climate change, COP26 president Alok Sharma said on Saturday. Speaking after days of meetings at the pre-COP26 climate event in Italy, Sharma said there was a consensus to do more to keep the 1.5 degrees Celsius target within reach, adding more needed to be done collectively in terms of national climate plans. The COP26 conference in Glasgow aims to secure more ambitious climate action from the nearly 200 countries that signed the 2015 Paris Agreement to limit global warming to well below 2.0 degrees Celsius - and to 1.5 degrees preferably - above pre-industrial levels.