We are currently in an exciting era of precision cosmology. With the release of the cosmic microwave background (CMB) data recorded by the Planck satellite, we are now in a position to accurately test the standard model of cosmology and particle physics. In this talk, I will present the latest results from my surveys to discover and characterise some of the most metal-poor, gas-rich galaxies currently known. Such near-pristine environments allow us to understand the early phases of dwarf galaxy evolution, probe the chemical signatures of the first stars, and study the primordial abundances of the light elements. I will discuss the current challenges faced by the standard model, and the future prospects to remedy some of the most pressing shortcomings. For example, new measurements of the primordial deuterium abundance and the primordial helium isotope ratio in near-pristine environments will lead to much improved limits on possible departures from the standard model. Figure shows the effective number of neutrino generations (N_eff) vs. the cosmic baryon density (Omega_b) derived from data from the CMB and Big-Bang Nucleosynthesis (BBN) predictions of light element abundances.