Read the passage given below and answer the questions that follow :

“States shall cooperate in the spirit of global partnership to conserve, protect and restore the health and integrity of the Earth’s ecosystem. In view of the different contributions of global environmental degradation, states have common but differentiated responsibilities. The developed countries acknowledge the responsibility that they bear in the international pursuit of sustainable development in view of the pressures their societies place on the global environment and of the technological and financial resources they command.'

(i) In which declaration the above decision was taken ?

(ii) What is sustainable development ?