Clarify condition checking in if else in C programming

How the condition checking execute in "if" condition?

int main()
{
int a =0;
printf("Enter the number\n");
scanf("%d",&a);
if(-600 <= a <= 600)
{
printf("True");
}
else
{
printf("False");
}
return 0;
}

The output is "True". Kindly clarify what is happening in that "if" condition?