Change html tag in template file tpl
if you want to use AMP for specific pages, you might want to take a look at the AMP module.

But if you still want to add the amp attribut to the &lt;HTML&gt; tag manually, here's one way:

Overwrite the html.tpl.php template by copying the original tpl file (modules/system/html.tpl.php) to your current theme (sites/all/themes/your_theme/). Then add the following code at the top of the file:

$amp = '';
if (arg(0) == 'node' &amp;&amp; is_numeric(arg(1))) {
    $nid = arg(1);
    $node = node_load($nid);
    $amp = $node-&gt;type == 'ir_news' ? 'amp' : '';
}  


Then, you just print the $amp variable inside the &lt;html&gt; tag.

The amp attribute will only be added to your ir_news pages.