Conditional WP_Query with PHP

Hey,

I am trying to conditionally perform a WP_Query depending on what page I am on. This is necessary because I want to pull a series of tags depending on what page I am on.

eg. The ‘Politics and Debates’ page will have posts from both the tags ‘Politics’ and ‘Debates’. My thoughts are to use this code in my page.php file:

$page = get_the_title( $page_id );
    echo $page;
    if ($page = 'Gender & Equality') {
        $tag_query = new WP_Query ( 'tag=Gender,Equality,Sexuality' );
    } elseif ($page ='Science & Research') {
        $tag_query = new WP_Query ( 'tag=Science,Research' );
    } elseif ($page ='Politics & Debates') {
        $tag_query = new WP_Query ( 'tag=Politics,Debates' );
    } elseif ($page ='Science & Environment') {
        $tag_query = new WP_Query ( 'tag=Science,Environment' );
    } elseif ($page ='Scientific Research') {
        $tag_query = new WP_Query ( 'tag=Research' );
    } elseif ($page ='Local Events') {
        $tag_query = new WP_Query ( 'tag=Events' );
    } else {
        echo 'No posts found';
    }

    while ( $tag_query -> have_posts() ) {
        $tag_query -> the_post();
        echo '<div class="masonry-item"><p>' . get_the_title() . '</p></div>';
    };

However, when I view any of my pages only posts from this query are loaded.

$tag_query = new WP_Query ( 'tag=Gender,Equality,Sexuality' );

Any suggestions would be appreciated.