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The classical Hadwiger conjecture dating back to 1940's states that any graphof chromatic number at least $r$ has the clique of order $r$ as a minor.Hadwiger's conjecture is an example of a well studied class of problems askinghow large a clique minor one can guarantee in a graph with certainrestrictions. One problem of this type asks what is the largest size of aclique minor in a graph on $n$ vertices of independence number $\alpha(G)$ atmost $r$. If true Hadwiger's conjecture would imply the existence of a cliqueminor of order $n/\alpha(G)$. Results of Kuhn and Osthus and Krivelevich andSudakov imply that if one assumes in addition that $G$ is $H$-free for somebipartite graph $H$ then one can find a polynomially larger clique minor. Thishas recently been extended to triangle free graphs by Dvo\v{r}\'ak andYepremyan, answering a question of Norin. We complete the picture and show thatthe same is true for arbitrary graph $H$, answering a question of Dvo\v{r}\'akand Yepremyan. In particular, we show that any $K_s$-free graph has a cliqueminor of order $c_s(n/\alpha(G))^{1+\frac{1}{10(s-2) }}$, for some constant$c_s$ depending only on $s$. The exponent in this result is tight up to aconstant factor in front of the $\frac{1}{s-2}$ term.

Clique minors in graphs with a forbidden subgraph