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HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allredirects garcontinue="Indigenous_People_of_the_Rio_Chixoy/Rio_Negro_basin|1486" />
  </query-continue>
  <query>
    <pages>
      <page pageid="613" ns="0" title="Indus River Basin" />
      <page pageid="632" ns="0" title="International Freshwater Treaties Regarding the Danube River Basin" />
      <page pageid="966" ns="0" title="Han River" />
      <page pageid="1292" ns="0" title="Drinking Water Supply in Phnom Penh" />
      <page pageid="1546" ns="0" title="Coastal Aquifer (Egypt, Israel, Palestine)" />
      <page pageid="1551" ns="0" title="Gaza Strip" />
      <page pageid="1654" ns="0" title="Treaty relating to cooperative development of the water resources of the Columbia River Basin" />
      <page pageid="1656" ns="0" title="Convention on cooperation for the protection and sustainable use of the River Danube" />
      <page pageid="2056" ns="0" title="Congo, Democratic Republic of (Kinshasa)" />
      <page pageid="2408" ns="0" title="Forming A Groundwater Sustainability Agency for Sonoma Valley Basin" />
    </pages>
  </query>
</api>