This project joins experimentalists and phenomenologists with complementary expertise from Switzerland (CH), Poland (PL) and Croatia (HR) covering critical research areas in neutrino physics. The main tasks to be undertaken are:A. Study of neutrino oscillation phenomenology with T2K, ESSnuSB and other experiments. We will analyse experimental and simulated data to understand new physics effects as well as some of the tensions among present neutrino experiments. In particular, we will try to explore if T2K data prefers any new physics beyond the standard three flavour scenario and try to propose a solution to the current tension between T2K and NO$\nu$A data. We will also work on phenomenological effects for existing and proposed neutrino mass and mixing models, testing them for various neutrino experimental oscillation baselines. We will also try to understand if a new physics scenario can be confused with the current systematic uncertainties and if the future improvement in the systematic error can resolve this problem. B. Setting up a special activity among ESSnuSB, NINJA and T2K groups for cross-section measurements. These experiments are sensitive in the sub-GeV region, where at present there is no measurement on the cross-section. Currently NINJA is measuring cross-section at the T2K energies i.e., 0.6 GeV. We will use this data to improve the cross-section models related to T2K experiment. Furthermore, placing the NINJA detector at the ground floor in the J-PARC facility will enable us to measure the cross-section at the ESSnuSB energies i.e., 0.4 GeV. In this project the idea is to put a small prototype NINJA detector in the J-PARC facility ground floor to understand the relevant background and perform the required simulation for the full detector setup. These cross-section information will be translated into improved systematic errors which will be used in the oscillation analysis.