This interesting “energy ladder” chart shows how the type of energy used for domestic cooking or heating relates to income level or, perhaps, standard of living. Lower income levels correlate with using dirtier, cheaper fuels, with consequent health and mortality impacts. The obvious improvement is to switch to cleaner fuels, but that kind of transition requires capital investments, time, and (probably) higher fuel costs.
As interesting as the chart might be, we need to clarify some points. First, the chart lists several categories of fuels, but electricity is not itself a fuel or energy source. A note on the chart mentions that “clean” electricity comes from nuclear or renewable sources, and the latter would include hydroelectric, solar, or wind power. However, many countries still generate significant portions of their electricity from coal, and some countries (i.e., China and India) are still building more coal-fired power plants.
Second, the chart is only qualitative. The relationships it shows are real, but it leaves out factors such as fuel cost and availability, the sizes and locations of populations using each level of fuel on the ladder, and the time it takes to make a transition to a cleaner energy source. None of this comes as a surprise, because the picture is always more complicated than at first glance.