PARIS, Oct 29 (Reuters) - AXA, France’s biggest insurer, on Friday announced measures to protect the climate, as companies look to burnish their environmentally-friendly credentials ahead of the COP26 world leaders’ summit on climate change. AXA said it would stop investing in and underwriting new upstream oil greenfield exploration projects unless they were carried out by companies with the most far-reaching and credible energy transition plans. It also increased its target for ‘green’ investment to 26 billion euros ($30.3 billion) by 2023 from 24 billion announced at the end of 2020. $1 = 0.8589 euros Reporting by Sudip Kar-Gupta; editing by Jason Neely