3 Policies Regarding CONSERVATION of World Heritage Properties
3.5 Factors affecting properties
Conservation of cultural and natural heritage is at the core of the Convention. Conservation includes effective and active measures that can be taken by States Parties to ensure the identification, protection, presentation and transmission of heritage.
There is no single definition of conservation in relation to both cultural and natural heritage. However, with regards to cultural heritage ‘all operations designed to understand a property, know its history and meaning, ensure its material safeguard, and, if required, its restoration and enhancement’ could be part of its conservation (Nara Document on Authenticity). Conservation of natural heritage refers to the protection, care, management and maintenance of ecosystems, habitats, wildlife species and populations, within or outside of their natural environments, in order to safeguard the natural conditions for their long-term permanence (IUCN).
The Conservation theme includes policies related to protection, management, monitoring, impact assessments, factors affecting the properties, tourism and sustainable development.
All types of pollution (residential or commercial) as well as garbage, solid waste.
Pollution of marine waters (For example: Ocean dumping, Bilge water discharge, Solid debris in marine environments). Ground water pollution (For example: Oil / chemical spills, Industrial effluent, Agricultural runoff, Household sewage/waste, Acid sulphate soils, Effluent discharge, Mine/tailings runoff). Surface water pollution (For example: Acid rain, Mine/tailings runoff, Agricultural runoff). Air pollution (For example: Excessive smoke or other airborne particulates, Dust, Local effects of emissions from use of fossil fuels). Solid waste (For example: Mine tailings, Litter, Industrial waste, Household rubbish). Input of excess energy (For example: Any inputs of heat and light that disturb ecosystems including inappropriate urban lighting, heat pollution, etc.).
Synthesis based on relevant Committee decisions
The World Heritage Committee recommends to enhance the regulation and monitoring of pollution, and to create management plans that consider options to address and to put in place adequate measures to mitigate the impact associated to the pollution, and its potential impact on the Outstanding Universal Value of the property, including the control of sources of pollution affecting the property (based on Case law on decisions on the State of Conservation). 
 See for example Decisions , , , , , .