In its current form, the Basel III definition of liquidity relies on two particular measures that have been proposed in the context of adopting a new global liquidity standard. As you surely know by now, these are the Liquidity Coverage Ratio (LCR) and the Net Stable Funding Ratio (NSFR).
It is broadly recognized that these measures of liquidity should be designed so that, from a macro-prudential perspective, they can be used as possible tools to help alleviating and mitigating a rise in systemic liquidity risk.