Both Koreas claimed to represent all Koreans, and for decades had enjoyed similar development levels.
"Flexibilities" to accommodate the members' different development levels have been used, the report says, "to justify non-compliance".
Development levels there are among the lowest in the world, despite being one of OPEC's biggest oil producers.
China and India argue that it is unfair to blame them for rising energy prices, and they have resisted calls to limit carbon emissions when their economies are trying to catch up with development levels in the West.
Wenger had just finished talking up Alex Iwobi's contribution after a promising half-hour from an occasional team-mate of Bellerín's in the development levels, valuable praise for a young player in need of reinforcement.
If Haiti is ever to catch up with its neighbours' development levels, says Medrano, it desperately needs both stable national institutions and $2.2bn from the international community to eliminate cholera and fund a "Marshall Plan for water and sanitation".
But the UN says that there is "no easy correlation" between poverty, development levels, inequality and crime, so it cannot be the whole answer.
If the forum succeeds in bringing flexibility to the system -- by recognizing the benefits of different government policies for countries at different development levels -- the result may be a more inclusive globalism, one less likely to be passing through "fragile times".
Other factors which may influence learning environment, such as urban economic development levels and the development levels, have not been considered in this study.
We follow the UN's classification method for development levels, using quartiles to divide the regions into low, medium, high, and very high development levels.
As a result, three groups (see Fig. 6, right) with distinct development levels became visible.
