protected void Application_BeginRequest(object sender, EventArgs e)
{
    //If upper case letters are found in the URL, redirect to lower case URL.
    if (Regex.IsMatch(HttpContext.Current.Request.RawUrl.ToString(), @"[A-Z]") == true)
    {
        if (Request.HttpMethod == "GET" && !(Request.RawUrl.Contains(".axd")))
        {
            string LowercaseURL = HttpContext.Current.Request.RawUrl.ToString().ToLower();
            Response.Clear();
            Response.Status = "301 Moved Permanently";
            Response.AddHeader("Location", LowercaseURL);
            Response.End();
        }
    }
}