In this guest blog, Sheikh Rokon, Founder and Secretary-General of Riverine People, a Dhaka based civil society organization shares his commentary on Bangladesh's switch from polluting clay-fired bricks to concrete-based bricks that are presented as 'eco-friendly' bricks within the country.

In this episode, Jeffrey Hart and Kiran Pereira talk about the different uses of sand, how we're using one non-renewable resource to get at another fossil resource, various methods of extraction and why we should care.